655656621 has 16 divisors (see below), whose sum is σ = 905333760. Its totient is φ = 421574720.

The previous prime is 655656619. The next prime is 655656667. The reversal of 655656621 is 126656556.

It is a cyclic number.

It is not a de Polignac number, because 655656621 - 2¹ = 655656619 is a prime.

It is a super-2 number, since 2×655656621² = 859771209322275282, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (655656821) 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, 88756 + ... + 95858.

It is an arithmetic number, because the mean of its divisors is an integer number (56583360).

Almost surely, 2^655656621 is an apocalyptic number.

It is an amenable number.

655656621 is a deficient number, since it is larger than the sum of its proper divisors (249677139).

655656621 is a wasteful number, since it uses less digits than its factorization.

655656621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8196.

The product of its digits is 324000, while the sum is 42.

The square root of 655656621 is about 25605.7927235225. The cubic root of 655656621 is about 868.7446646257.

The spelling of 655656621 in words is "six hundred fifty-five million, six hundred fifty-six thousand, six hundred twenty-one".