51565656 has 32 divisors (see below), whose sum is σ = 129371760. Its totient is φ = 17127552.

The previous prime is 51565649. The next prime is 51565669. The reversal of 51565656 is 65656515.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3366 + ... + 10698.

Almost surely, 2^51565656 is an apocalyptic number.

It is an amenable number.

51565656 is an abundant number, since it is smaller than the sum of its proper divisors (77806104).

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

51565656 is a wasteful number, since it uses less digits than its factorization.

51565656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7635 (or 7631 counting only the distinct ones).

The product of its digits is 135000, while the sum is 39.

The square root of 51565656 is about 7180.9230604429. The cubic root of 51565656 is about 372.2089818942.

The spelling of 51565656 in words is "fifty-one million, five hundred sixty-five thousand, six hundred fifty-six".