256786441081 has 9 divisors (see below), whose sum is σ = 259219651341. Its totient is φ = 254375874144.

The previous prime is 256786441019. The next prime is 256786441097. The reversal of 256786441081 is 180144687652.

The square root of 256786441081 is 506741.

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

It can be written as a sum of positive squares in 4 ways, for example, as 142664088681 + 114122352400 = 377709^2 + 337820^2 .

It is not a de Polignac number, because 256786441081 - 2¹⁵ = 256786408313 is a prime.

It is a super-2 number, since 2×256786441081² (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 (256786441001) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 55232445 + ... + 55237093.

Almost surely, 2^256786441081 is an apocalyptic number.

256786441081 is the 506741-st square number.

256786441081 is the 253371-st centered octagonal number.

It is an amenable number.

256786441081 is a deficient number, since it is larger than the sum of its proper divisors (2433210260).

256786441081 is an frugal number, since it uses more digits than its factorization.

256786441081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9516 (or 4758 counting only the distinct ones).

The product of its (nonzero) digits is 2580480, while the sum is 52.

The spelling of 256786441081 in words is "two hundred fifty-six billion, seven hundred eighty-six million, four hundred forty-one thousand, eighty-one".