256990386 has 16 divisors (see below), whose sum is σ = 515537568. Its totient is φ = 85404000.

The previous prime is 256990381. The next prime is 256990399. The reversal of 256990386 is 683099652.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256990381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62715 + ... + 66686.

It is an arithmetic number, because the mean of its divisors is an integer number (32221098).

Almost surely, 2^256990386 is an apocalyptic number.

256990386 is an abundant number, since it is smaller than the sum of its proper divisors (258547182).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256990386 is a wasteful number, since it uses less digits than its factorization.

256990386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129737.

The product of its (nonzero) digits is 699840, while the sum is 48.

The square root of 256990386 is about 16030.9196866555. The cubic root of 256990386 is about 635.7781899268.

The spelling of 256990386 in words is "two hundred fifty-six million, nine hundred ninety thousand, three hundred eighty-six".