256105687 has 2 divisors, whose sum is σ = 256105688. Its totient is φ = 256105686.

The previous prime is 256105673. The next prime is 256105709. The reversal of 256105687 is 786501652.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256105687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256105627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128052843 + 128052844.

It is an arithmetic number, because the mean of its divisors is an integer number (128052844).

Almost surely, 2^256105687 is an apocalyptic number.

256105687 is a deficient number, since it is larger than the sum of its proper divisors (1).

256105687 is an equidigital number, since it uses as much as digits as its factorization.

256105687 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 256105687 is about 16003.3023779469. The cubic root of 256105687 is about 635.0477877525.

The spelling of 256105687 in words is "two hundred fifty-six million, one hundred five thousand, six hundred eighty-seven".