51503806638 has 32 divisors (see below), whose sum is σ = 117546229920. Its totient is φ = 16703936640.

The previous prime is 51503806621. The next prime is 51503806667. The reversal of 51503806638 is 83660830515.

51503806638 is a `hidden beast` number, since 5 + 1 + 5 + 0 + 3 + 8 + 0 + 6 + 638 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 51503806593 and 51503806602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12886843 + ... + 12890838.

It is an arithmetic number, because the mean of its divisors is an integer number (3673319685).

Almost surely, 2^51503806638 is an apocalyptic number.

51503806638 is an abundant number, since it is smaller than the sum of its proper divisors (66042423282).

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

51503806638 is a wasteful number, since it uses less digits than its factorization.

51503806638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25777729 (or 25777723 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 51503806638 in words is "fifty-one billion, five hundred three million, eight hundred six thousand, six hundred thirty-eight".