256403660131 has 16 divisors (see below), whose sum is σ = 279827707104. Its totient is φ = 233988378624.

The previous prime is 256403660119. The next prime is 256403660137. The reversal of 256403660131 is 131066304652.

It is not a de Polignac number, because 256403660131 - 2⁷ = 256403660003 is a prime.

It is a super-2 number, since 2×256403660131² (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 (256403660137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1179990 + ... + 1380283.

It is an arithmetic number, because the mean of its divisors is an integer number (17489231694).

Almost surely, 2^256403660131 is an apocalyptic number.

256403660131 is a deficient number, since it is larger than the sum of its proper divisors (23424046973).

256403660131 is a wasteful number, since it uses less digits than its factorization.

256403660131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2560470.

The product of its (nonzero) digits is 77760, while the sum is 37.

Adding to 256403660131 its reverse (131066304652), we get a palindrome (387469964783).

The spelling of 256403660131 in words is "two hundred fifty-six billion, four hundred three million, six hundred sixty thousand, one hundred thirty-one".