2256643266491 has 2 divisors, whose sum is σ = 2256643266492. Its totient is φ = 2256643266490.

The previous prime is 2256643266431. The next prime is 2256643266529. The reversal of 2256643266491 is 1946623466522.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2256643266491 - 2³⁴ = 2239463397307 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (2256643266431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1128321633245 + 1128321633246.

It is an arithmetic number, because the mean of its divisors is an integer number (1128321633246).

Almost surely, 2^{2256643266491} is an apocalyptic number.

2256643266491 is a deficient number, since it is larger than the sum of its proper divisors (1).

2256643266491 is an equidigital number, since it uses as much as digits as its factorization.

2256643266491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22394880, while the sum is 56.

The spelling of 2256643266491 in words is "two trillion, two hundred fifty-six billion, six hundred forty-three million, two hundred sixty-six thousand, four hundred ninety-one".