Yes, nothing to do with prime numbers. SHA-2 uses some constants. A lot of cryptography needs constants for various reasons. There is always some concern that the creator chose specific constants that weaken or give them a backdoor to the crypto scheme. To reduce this concern, they often choose constants from some simple mathematical basis, perhaps the numbers '1234567890', or digits of pi, etc. In SHA-2's case, they used the first 32 bits of the fractional parts of the square roots of the first n primes.
The numbers they use are not primes, nor are primes useful in any way for attacking SHA. The algorithm still has nothing to do with prime numbers.
The numbers they use are not primes, nor are primes useful in any way for attacking SHA. The algorithm still has nothing to do with prime numbers.