51000616665 has 24 divisors (see below), whose sum is σ = 90790289928. Its totient is φ = 26465184000.

The previous prime is 51000616643. The next prime is 51000616699. The reversal of 51000616665 is 56661600015.

It can be written as a sum of positive squares in 4 ways, for example, as 15416698896 + 35583917769 = 124164^2 + 188637^2 .

It is not a de Polignac number, because 51000616665 - 2⁵ = 51000616633 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15313836 + ... + 15317165.

It is an arithmetic number, because the mean of its divisors is an integer number (3782928747).

Almost surely, 2^51000616665 is an apocalyptic number.

It is an amenable number.

51000616665 is a deficient number, since it is larger than the sum of its proper divisors (39789673263).

51000616665 is a wasteful number, since it uses less digits than its factorization.

51000616665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30631049 (or 30631046 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The spelling of 51000616665 in words is "fifty-one billion, six hundred sixteen thousand, six hundred sixty-five".