256005155 has 24 divisors (see below), whose sum is σ = 359559648. Its totient is φ = 174467328.

The previous prime is 256005143. The next prime is 256005173. The reversal of 256005155 is 551500652.

It is not a de Polignac number, because 256005155 - 2⁸ = 256004899 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 37787 + ... + 44043.

It is an arithmetic number, because the mean of its divisors is an integer number (14981652).

Almost surely, 2^256005155 is an apocalyptic number.

256005155 is a deficient number, since it is larger than the sum of its proper divisors (103554493).

256005155 is a wasteful number, since it uses less digits than its factorization.

256005155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6443 (or 6436 counting only the distinct ones).

The product of its (nonzero) digits is 7500, while the sum is 29.

The square root of 256005155 is about 16000.1610929390. The cubic root of 256005155 is about 634.9646827651.

The spelling of 256005155 in words is "two hundred fifty-six million, five thousand, one hundred fifty-five".