5656621621 has 16 divisors (see below), whose sum is σ = 6647655168. Its totient is φ = 4712227200.

The previous prime is 5656621603. The next prime is 5656621627. The reversal of 5656621621 is 1261266565.

It is a cyclic number.

It is not a de Polignac number, because 5656621621 - 2⁵ = 5656621589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5656621627) 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, 38011 + ... + 112951.

It is an arithmetic number, because the mean of its divisors is an integer number (415478448).

Almost surely, 2^5656621621 is an apocalyptic number.

It is an amenable number.

5656621621 is a deficient number, since it is larger than the sum of its proper divisors (991033547).

5656621621 is a wasteful number, since it uses less digits than its factorization.

5656621621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75252.

The product of its digits is 129600, while the sum is 40.

The square root of 5656621621 is about 75210.5153618827. The cubic root of 5656621621 is about 1781.7730114847.

It can be divided in two parts, 56566 and 21621, that added together give a palindrome (78187).

The spelling of 5656621621 in words is "five billion, six hundred fifty-six million, six hundred twenty-one thousand, six hundred twenty-one".