256656731769 has 27 divisors (see below), whose sum is σ = 378887462863. Its totient is φ = 167417358432.

The previous prime is 256656731761. The next prime is 256656731777. The reversal of 256656731769 is 967137656652.

The square root of 256656731769 is 506613.

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

256656731769 is a `hidden beast` number, since 2 + 5 + 6 + 6 + 567 + 3 + 1 + 7 + 69 = 666.

It is an interprime number because it is at equal distance from previous prime (256656731761) and next prime (256656731777).

It can be written as a sum of positive squares in only one way, i.e., 81524525625 + 175132206144 = 285525^2 + 418488^2 .

It is not a de Polignac number, because 256656731769 - 2³ = 256656731761 is a prime.

It is a super-2 number, since 2×256656731769² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256656731761) 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, 71430637 + ... + 71434229.

Almost surely, 2^256656731769 is an apocalyptic number.

256656731769 is the 506613-rd square number.

256656731769 is the 253307-th centered octagonal number.

It is an amenable number.

256656731769 is a deficient number, since it is larger than the sum of its proper divisors (122230731094).

256656731769 is an frugal number, since it uses more digits than its factorization.

256656731769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7286 (or 3643 counting only the distinct ones).

The product of its digits is 85730400, while the sum is 63.

The spelling of 256656731769 in words is "two hundred fifty-six billion, six hundred fifty-six million, seven hundred thirty-one thousand, seven hundred sixty-nine".