51361575840 has 72 divisors (see below), whose sum is σ = 175271382468. Its totient is φ = 13696419840.

The previous prime is 51361575803. The next prime is 51361575851. The reversal of 51361575840 is 4857516315.

51361575840 is a `hidden beast` number, since 5 + 1 + 3 + 61 + 5 + 7 + 584 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 50263846416 + 1097729424 = 224196^2 + 33132^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×51361575840² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17832441 + ... + 17835320.

Almost surely, 2^51361575840 is an apocalyptic number.

It is an amenable number.

51361575840 is an abundant number, since it is smaller than the sum of its proper divisors (123909806628).

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

51361575840 is a wasteful number, since it uses less digits than its factorization.

51361575840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35667782 (or 35667771 counting only the distinct ones).

The product of its (nonzero) digits is 504000, while the sum is 45.

The spelling of 51361575840 in words is "fifty-one billion, three hundred sixty-one million, five hundred seventy-five thousand, eight hundred forty".