51640623938 has 6 divisors (see below), whose sum is σ = 77461417971. Its totient is φ = 25820151282.

The previous prime is 51640623917. The next prime is 51640623953. The reversal of 51640623938 is 83932604615.

It can be written as a sum of positive squares in only one way, i.e., 25820311969 + 25820311969 = 160687^2 + 160687^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=160687.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 51640623892 and 51640623901.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 241031 + ... + 401717.

Almost surely, 2^51640623938 is an apocalyptic number.

51640623938 is a deficient number, since it is larger than the sum of its proper divisors (25820794033).

51640623938 is an frugal number, since it uses more digits than its factorization.

51640623938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321376 (or 160689 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 47.

The spelling of 51640623938 in words is "fifty-one billion, six hundred forty million, six hundred twenty-three thousand, nine hundred thirty-eight".