256978155 has 64 divisors (see below), whose sum is σ = 481489920. Its totient is φ = 114622464.

The previous prime is 256978133. The next prime is 256978207. The reversal of 256978155 is 551879652.

It is a happy number.

It is not a de Polignac number, because 256978155 - 2¹³ = 256969963 is a prime.

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, 999787 + ... + 1000043.

It is an arithmetic number, because the mean of its divisors is an integer number (7523280).

Almost surely, 2^256978155 is an apocalyptic number.

256978155 is a deficient number, since it is larger than the sum of its proper divisors (224511765).

256978155 is a wasteful number, since it uses less digits than its factorization.

256978155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468.

The product of its digits is 756000, while the sum is 48.

The square root of 256978155 is about 16030.5382005721. The cubic root of 256978155 is about 635.7681035230.

The spelling of 256978155 in words is "two hundred fifty-six million, nine hundred seventy-eight thousand, one hundred fifty-five".