256635131 has 4 divisors (see below), whose sum is σ = 259280952. Its totient is φ = 253989312.

The previous prime is 256635121. The next prime is 256635133. The reversal of 256635131 is 131536652.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256635131 is a prime.

It is a super-2 number, since 2×256635131² = 131723180926774322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256635133) 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 3 ways as a sum of consecutive naturals, for example, 1322765 + ... + 1322958.

It is an arithmetic number, because the mean of its divisors is an integer number (64820238).

Almost surely, 2^256635131 is an apocalyptic number.

256635131 is a deficient number, since it is larger than the sum of its proper divisors (2645821).

256635131 is an equidigital number, since it uses as much as digits as its factorization.

256635131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2645820.

The product of its digits is 16200, while the sum is 32.

The square root of 256635131 is about 16019.8355484693. The cubic root of 256635131 is about 635.4850952580.

The spelling of 256635131 in words is "two hundred fifty-six million, six hundred thirty-five thousand, one hundred thirty-one".