256464991 has 2 divisors, whose sum is σ = 256464992. Its totient is φ = 256464990.

The previous prime is 256464979. The next prime is 256465003. The reversal of 256464991 is 199464652.

It is a balanced prime because it is at equal distance from previous prime (256464979) and next prime (256465003).

It is a cyclic number.

It is not a de Polignac number, because 256464991 - 2²⁷ = 122247263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256464911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128232495 + 128232496.

It is an arithmetic number, because the mean of its divisors is an integer number (128232496).

Almost surely, 2^256464991 is an apocalyptic number.

256464991 is a deficient number, since it is larger than the sum of its proper divisors (1).

256464991 is an equidigital number, since it uses as much as digits as its factorization.

256464991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 466560, while the sum is 46.

The square root of 256464991 is about 16014.5243763279. The cubic root of 256464991 is about 635.3446295105.

The spelling of 256464991 in words is "two hundred fifty-six million, four hundred sixty-four thousand, nine hundred ninety-one".