256761404987 has 2 divisors, whose sum is σ = 256761404988. Its totient is φ = 256761404986.

The previous prime is 256761404953. The next prime is 256761405053. The reversal of 256761404987 is 789404167652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256761404987 - 2⁶ = 256761404923 is a prime.

It is not a weakly prime, because it can be changed into another prime (256761404917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128380702493 + 128380702494.

It is an arithmetic number, because the mean of its divisors is an integer number (128380702494).

Almost surely, 2^256761404987 is an apocalyptic number.

256761404987 is a deficient number, since it is larger than the sum of its proper divisors (1).

256761404987 is an equidigital number, since it uses as much as digits as its factorization.

256761404987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20321280, while the sum is 59.

The spelling of 256761404987 in words is "two hundred fifty-six billion, seven hundred sixty-one million, four hundred four thousand, nine hundred eighty-seven".