256151891 has 4 divisors (see below), whose sum is σ = 259394400. Its totient is φ = 252909384.

The previous prime is 256151837. The next prime is 256151899. The reversal of 256151891 is 198151652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 256151891 - 2⁶ = 256151827 is a prime.

It is a super-2 number, since 2×256151891² = 131227582525751762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256151899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1621136 + ... + 1621293.

It is an arithmetic number, because the mean of its divisors is an integer number (64848600).

Almost surely, 2^256151891 is an apocalyptic number.

256151891 is a deficient number, since it is larger than the sum of its proper divisors (3242509).

256151891 is an equidigital number, since it uses as much as digits as its factorization.

256151891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3242508.

The product of its digits is 21600, while the sum is 38.

The square root of 256151891 is about 16004.7458898915. The cubic root of 256151891 is about 635.0859750910.

The spelling of 256151891 in words is "two hundred fifty-six million, one hundred fifty-one thousand, eight hundred ninety-one".