256311091 has 8 divisors (see below), whose sum is σ = 272960064. Its totient is φ = 239836800.

The previous prime is 256311061. The next prime is 256311109. The reversal of 256311091 is 190113652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256311091 is a prime.

It is a super-2 number, since 2×256311091² = 131390750739220562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256311031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40635 + ... + 46516.

It is an arithmetic number, because the mean of its divisors is an integer number (34120008).

Almost surely, 2^256311091 is an apocalyptic number.

256311091 is a deficient number, since it is larger than the sum of its proper divisors (16648973).

256311091 is a wasteful number, since it uses less digits than its factorization.

256311091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87341.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 256311091 is about 16009.7186421249. The cubic root of 256311091 is about 635.2175178098.

It can be divided in two parts, 2563110 and 91, that added together give a square (2563201 = 1601²).

The spelling of 256311091 in words is "two hundred fifty-six million, three hundred eleven thousand, ninety-one".