256761 has 12 divisors (see below), whose sum is σ = 379392. Its totient is φ = 167256.

The previous prime is 256757. The next prime is 256771. The reversal of 256761 is 167652.

It is not a de Polignac number, because 256761 - 2² = 256757 is a prime.

It is a super-2 number, since 2×256761² = 131852422242, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (256721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120 + ... + 726.

It is an arithmetic number, because the mean of its divisors is an integer number (31616).

2²⁵⁶⁷⁶¹ is an apocalyptic number.

It is an amenable number.

256761 is a deficient number, since it is larger than the sum of its proper divisors (122631).

256761 is a wasteful number, since it uses less digits than its factorization.

256761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660 (or 657 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 256761 is about 506.7158967311. The cubic root of 256761 is about 63.5588971398.

It can be divided in two parts, 2567 and 61, that added together give a triangular number (2628 = T₇₂).

The spelling of 256761 in words is "two hundred fifty-six thousand, seven hundred sixty-one".