256881 has 4 divisors (see below), whose sum is σ = 342512. Its totient is φ = 171252.
The previous prime is 256877. The next prime is 256889. The reversal of 256881 is 188652.
It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.
It is not a de Polignac number, because 256881 - 22 = 256877 is a prime.
It is a super-2 number, since 2×2568812 = 131975696322, which contains 22 as substring.
It is a D-number.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (256889) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42811 + ... + 42816.
It is an arithmetic number, because the mean of its divisors is an integer number (85628).
2256881 is an apocalyptic number.
It is an amenable number.
256881 is a deficient number, since it is larger than the sum of its proper divisors (85631).
256881 is an equidigital number, since it uses as much as digits as its factorization.
256881 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 85630.
The product of its digits is 3840, while the sum is 30.
The square root of 256881 is about 506.8342924468. The cubic root of 256881 is about 63.5687972411.
The spelling of 256881 in words is "two hundred fifty-six thousand, eight hundred eighty-one".
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