256999990 has 48 divisors (see below), whose sum is σ = 503797536. Its totient is φ = 94348800.

The previous prime is 256999987. The next prime is 256999991. The reversal of 256999990 is 99999652.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256999991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 406975 + ... + 407605.

It is an arithmetic number, because the mean of its divisors is an integer number (10495782).

Almost surely, 2^256999990 is an apocalyptic number.

256999990 is a deficient number, since it is larger than the sum of its proper divisors (246797546).

256999990 is a wasteful number, since it uses less digits than its factorization.

256999990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 905 (or 892 counting only the distinct ones).

The product of its (nonzero) digits is 3542940, while the sum is 58.

The square root of 256999990 is about 16031.2192299900. The cubic root of 256999990 is about 635.7861097272.

The spelling of 256999990 in words is "two hundred fifty-six million, nine hundred ninety-nine thousand, nine hundred ninety".