256161555 has 64 divisors (see below), whose sum is σ = 493355520. Its totient is φ = 125359488.

The previous prime is 256161547. The next prime is 256161583. The reversal of 256161555 is 555161652.

256161555 = 4433² + 4434² + ... + 4445².

256161555 is a `hidden beast` number, since 25 + 616 + 15 + 5 + 5 = 666.

It is not a de Polignac number, because 256161555 - 2³ = 256161547 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 398064 + ... + 398706.

It is an arithmetic number, because the mean of its divisors is an integer number (7708680).

Almost surely, 2^256161555 is an apocalyptic number.

256161555 is a deficient number, since it is larger than the sum of its proper divisors (237193965).

256161555 is a wasteful number, since it uses less digits than its factorization.

256161555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897 (or 891 counting only the distinct ones).

The product of its digits is 45000, while the sum is 36.

The square root of 256161555 is about 16005.0477974919. The cubic root of 256161555 is about 635.0939617503.

The spelling of 256161555 in words is "two hundred fifty-six million, one hundred sixty-one thousand, five hundred fifty-five".