256060991 has 2 divisors, whose sum is σ = 256060992. Its totient is φ = 256060990.

The previous prime is 256060963. The next prime is 256061011. The reversal of 256060991 is 199060652.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256060991 is a prime.

It is a super-2 number, since 2×256060991² = 131134462223804162, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256060901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128030495 + 128030496.

It is an arithmetic number, because the mean of its divisors is an integer number (128030496).

Almost surely, 2^256060991 is an apocalyptic number.

256060991 is a deficient number, since it is larger than the sum of its proper divisors (1).

256060991 is an equidigital number, since it uses as much as digits as its factorization.

256060991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29160, while the sum is 38.

The square root of 256060991 is about 16001.9058552411. The cubic root of 256060991 is about 635.0108423966.

The spelling of 256060991 in words is "two hundred fifty-six million, sixty thousand, nine hundred ninety-one".