51565515666 has 32 divisors (see below), whose sum is σ = 122988561408. Its totient is φ = 14092438800.

The previous prime is 51565515637. The next prime is 51565515667. The reversal of 51565515666 is 66651556515.

It is not an unprimeable number, because it can be changed into a prime (51565515667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26689260 + ... + 26691191.

It is an arithmetic number, because the mean of its divisors is an integer number (3843392544).

Almost surely, 2^51565515666 is an apocalyptic number.

51565515666 is an abundant number, since it is smaller than the sum of its proper divisors (71423045742).

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

51565515666 is a wasteful number, since it uses less digits than its factorization.

51565515666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53380486.

The product of its digits is 4050000, while the sum is 51.

The spelling of 51565515666 in words is "fifty-one billion, five hundred sixty-five million, five hundred fifteen thousand, six hundred sixty-six".