51856465815 has 128 divisors (see below), whose sum is σ = 115091159040. Its totient is φ = 21521894400.

The previous prime is 51856465777. The next prime is 51856465819.

51856465815 is a `hidden beast` number, since 5 + 1 + 8 + 56 + 4 + 6 + 581 + 5 = 666.

51856465815 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 51856465815 - 2⁶ = 51856465751 is a prime.

It is a super-2 number, since 2×51856465815² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51856465819) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 8905605 + ... + 8911425.

It is an arithmetic number, because the mean of its divisors is an integer number (899149680).

Almost surely, 2^51856465815 is an apocalyptic number.

51856465815 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

51856465815 is an abundant number, since it is smaller than the sum of its proper divisors (63234693225).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51856465815 is a wasteful number, since it uses less digits than its factorization.

51856465815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6710 (or 6704 counting only the distinct ones).

The product of its digits is 5760000, while the sum is 54.

Subtracting from 51856465815 its product of digits (5760000), we obtain a palindrome (51850705815).

The spelling of 51856465815 in words is "fifty-one billion, eight hundred fifty-six million, four hundred sixty-five thousand, eight hundred fifteen".