256819931881 has 4 divisors (see below), whose sum is σ = 256825437264. Its totient is φ = 256814426500.

The previous prime is 256819931873. The next prime is 256819931941. The reversal of 256819931881 is 188139918652.

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 a cyclic number.

It is not a de Polignac number, because 256819931881 - 2³ = 256819931873 is a prime.

It is a super-2 number, since 2×256819931881² (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 (256819931281) 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, 2682115 + ... + 2776216.

It is an arithmetic number, because the mean of its divisors is an integer number (64206359316).

Almost surely, 2^256819931881 is an apocalyptic number.

It is an amenable number.

256819931881 is a deficient number, since it is larger than the sum of its proper divisors (5505383).

256819931881 is an equidigital number, since it uses as much as digits as its factorization.

256819931881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5505382.

The product of its digits is 7464960, while the sum is 61.

The spelling of 256819931881 in words is "two hundred fifty-six billion, eight hundred nineteen million, nine hundred thirty-one thousand, eight hundred eighty-one".