51515678831 has 4 divisors (see below), whose sum is σ = 52611757152. Its totient is φ = 50419600512.

The previous prime is 51515678801. The next prime is 51515678891. The reversal of 51515678831 is 13887651515.

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-51515678831 is a prime.

It is a super-2 number, since 2×51515678831² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51515678831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51515678801) 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, 548039090 + ... + 548039183.

It is an arithmetic number, because the mean of its divisors is an integer number (13152939288).

Almost surely, 2^51515678831 is an apocalyptic number.

51515678831 is a deficient number, since it is larger than the sum of its proper divisors (1096078321).

51515678831 is a wasteful number, since it uses less digits than its factorization.

51515678831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1096078320.

The product of its digits is 1008000, while the sum is 50.

The spelling of 51515678831 in words is "fifty-one billion, five hundred fifteen million, six hundred seventy-eight thousand, eight hundred thirty-one".