RSA cryptography strength comes from the hardness (or so we believe) of factoring big numbers. For key lengths over 2048 bits, it is infeasible for current or near-future computers to factor those numbers in a reasonable time.
But what about the human brain? There are people with remarkable math abilities; for example, savants that can perform many complex calculations. Imagine a person who is fixated on factoring composite numbers. Maybe his or her abilities could be augmented by drugs.
Is this a genuine concern when designing cryptographic ciphers? Could an evil organization employ one of these people to crack cryptographic keys (for any modern cipher)? Maybe there is some real-life example?

Mental calculators do not have the result appearing in their brain by staring at the input. They follow some (broadly sequential) algorithm¹. And computers vastly outperform them when they use the same algorithm. That was already by at least a factor >100 for inexpensive personal computers in the late 1970s.
For example, the record for 10 multiplications of two 8-digit numbers is stated at 162 seconds (source). Even by a schoolbook algorithm working in decimal, that task at worse requires 640 elementary operations involving 4 decimal digits. An Apple ][ with a proper (6502 assembly) program would do this well under 1 second, including extracting the digits from and storing the results into screen "text" memory.
I conclude we can entirely discount human prodigies outperform computers at breaking any proper crypto.

Update: the same source states as a record mentally finding in 6'38" the factors of 20 random five-digit composites, which is considerably easier than for proper RSA biprimes. This is telling about the human brain not being good at factoring.
Update2: It's also stated as a performance factoring a 16 (resp. 15, 14)-digit integer known to be the product of four consecutive primes at an average of 23'24" (resp. 13'21", 6'06"). I guesstimate an Apple ][ can outperform that by a factor ≈10000 even when working in decimal, using a single step of Fermat's method for each of three factorizations.

¹ See a performer multiplying two 20-digit numbers in 5'26"; world record is stated as 2'48".
