51206856868 has 12 divisors (see below), whose sum is σ = 90182777692. Its totient is φ = 25440348960.

The previous prime is 51206856859. The next prime is 51206856881. The reversal of 51206856868 is 86865860215.

It can be written as a sum of positive squares in 2 ways, for example, as 8166375424 + 43040481444 = 90368^2 + 207462^2 .

It is a hoax number, since the sum of its digits (55) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40769163 + ... + 40770418.

Almost surely, 2^51206856868 is an apocalyptic number.

It is an amenable number.

51206856868 is a deficient number, since it is larger than the sum of its proper divisors (38975920824).

51206856868 is a wasteful number, since it uses less digits than its factorization.

51206856868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81539742 (or 81539740 counting only the distinct ones).

The product of its (nonzero) digits is 5529600, while the sum is 55.

The spelling of 51206856868 in words is "fifty-one billion, two hundred six million, eight hundred fifty-six thousand, eight hundred sixty-eight".