51990870722 has 54 divisors (see below), whose sum is σ = 93865909779. Its totient is φ = 21534012360.

The previous prime is 51990870719. The next prime is 51990870773. The reversal of 51990870722 is 22707809915.

51990870722 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 25995435361 + 25995435361 = 161231^2 + 161231^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=161231.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 69973883 + ... + 69974625.

Almost surely, 2^51990870722 is an apocalyptic number.

51990870722 is a deficient number, since it is larger than the sum of its proper divisors (41875039057).

51990870722 is an frugal number, since it uses more digits than its factorization.

51990870722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1564 (or 783 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 50.

Multiplying 51990870722 by its sum of digits (50), we get a square (2599543536100 = 1612310²).

The spelling of 51990870722 in words is "fifty-one billion, nine hundred ninety million, eight hundred seventy thousand, seven hundred twenty-two".