51801687765 has 24 divisors (see below), whose sum is σ = 89804178360. Its totient is φ = 27623078784.

The previous prime is 51801687757. The next prime is 51801687787. The reversal of 51801687765 is 56778610815.

51801687765 is a `hidden beast` number, since 518 + 0 + 1 + 68 + 7 + 7 + 65 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 31170961809 + 20630725956 = 176553^2 + 143634^2 .

It is not a de Polignac number, because 51801687765 - 2³ = 51801687757 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 196471 + ... + 377099.

It is an arithmetic number, because the mean of its divisors is an integer number (3741840765).

Almost surely, 2^51801687765 is an apocalyptic number.

It is an amenable number.

51801687765 is a deficient number, since it is larger than the sum of its proper divisors (38002490595).

51801687765 is a wasteful number, since it uses less digits than its factorization.

51801687765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187013 (or 187010 counting only the distinct ones).

The product of its (nonzero) digits is 2822400, while the sum is 54.

The spelling of 51801687765 in words is "fifty-one billion, eight hundred one million, six hundred eighty-seven thousand, seven hundred sixty-five".