51565657 has 16 divisors (see below), whose sum is σ = 60903360. Its totient is φ = 43041600.

The previous prime is 51565649. The next prime is 51565669. The reversal of 51565657 is 75656515.

It is a cyclic number.

It is not a de Polignac number, because 51565657 - 2³ = 51565649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51565697) 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, 29319 + ... + 31027.

It is an arithmetic number, because the mean of its divisors is an integer number (3806460).

Almost surely, 2^51565657 is an apocalyptic number.

It is an amenable number.

51565657 is a deficient number, since it is larger than the sum of its proper divisors (9337703).

51565657 is a wasteful number, since it uses less digits than its factorization.

51565657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1944.

The product of its digits is 157500, while the sum is 40.

The square root of 51565657 is about 7180.9231300718. The cubic root of 51565657 is about 372.2089843002.

The spelling of 51565657 in words is "fifty-one million, five hundred sixty-five thousand, six hundred fifty-seven".