51138615860 has 24 divisors (see below), whose sum is σ = 107400478920. Its totient is φ = 20453658624.

The previous prime is 51138615851. The next prime is 51138615877. The reversal of 51138615860 is 6851683115.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 9265936 + 51129349924 = 3044^2 + 226118^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136256 + ... + 347624.

It is an arithmetic number, because the mean of its divisors is an integer number (4475019955).

Almost surely, 2^51138615860 is an apocalyptic number.

It is an amenable number.

51138615860 is an abundant number, since it is smaller than the sum of its proper divisors (56261863060).

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

51138615860 is a wasteful number, since it uses less digits than its factorization.

51138615860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223475 (or 223473 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 44.

The spelling of 51138615860 in words is "fifty-one billion, one hundred thirty-eight million, six hundred fifteen thousand, eight hundred sixty".