256992961 has 27 divisors (see below), whose sum is σ = 292515433. Its totient is φ = 225716480.

The previous prime is 256992959. The next prime is 256992971. The reversal of 256992961 is 169299652.

The square root of 256992961 is 16031.

It is a perfect power (a square), and thus also a powerful number.

256992961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 18105025 + 238887936 = 4255^2 + 15456^2 .

It is not a de Polignac number, because 256992961 - 2¹ = 256992959 is a prime.

It is a Duffinian number.

Its product of digits (524880) is a multiple of the sum of its prime divisors (81).

It is not an unprimeable number, because it can be changed into a prime (256992941) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 6268101 + ... + 6268141.

Almost surely, 2^256992961 is an apocalyptic number.

256992961 is the 16031-st square number.

256992961 is the 8016-th centered octagonal number.

It is an amenable number.

256992961 is a deficient number, since it is larger than the sum of its proper divisors (35522472).

256992961 is an equidigital number, since it uses as much as digits as its factorization.

256992961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 81 counting only the distinct ones).

The product of its digits is 524880, while the sum is 49.

The cubic root of 256992961 is about 635.7803133828.

Multiplying 256992961 by its sum of digits (49), we get a square (12592655089 = 112217²).

The spelling of 256992961 in words is "two hundred fifty-six million, nine hundred ninety-two thousand, nine hundred sixty-one".