51115115631 has 4 divisors (see below), whose sum is σ = 68153487512. Its totient is φ = 34076743752.

The previous prime is 51115115621. The next prime is 51115115633. The reversal of 51115115631 is 13651151115.

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

It is not a de Polignac number, because 51115115631 - 2¹⁹ = 51114591343 is a prime.

It is a super-2 number, since 2×51115115631² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51115115633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8519185936 + ... + 8519185941.

It is an arithmetic number, because the mean of its divisors is an integer number (17038371878).

Almost surely, 2^51115115631 is an apocalyptic number.

51115115631 is a deficient number, since it is larger than the sum of its proper divisors (17038371881).

51115115631 is a wasteful number, since it uses less digits than its factorization.

51115115631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17038371880.

The product of its digits is 2250, while the sum is 30.

Adding to 51115115631 its reverse (13651151115), we get a palindrome (64766266746).

The spelling of 51115115631 in words is "fifty-one billion, one hundred fifteen million, one hundred fifteen thousand, six hundred thirty-one".