656621 has 8 divisors (see below), whose sum is σ = 790080. Its totient is φ = 533088.

The previous prime is 656609. The next prime is 656651. The reversal of 656621 is 126656.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 656621 - 2¹⁰ = 655597 is a prime.

It is a super-2 number, since 2×656621² = 862302275282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2336 + ... + 2601.

It is an arithmetic number, because the mean of its divisors is an integer number (98760).

2⁶⁵⁶⁶²¹ is an apocalyptic number.

It is an amenable number.

656621 is a deficient number, since it is larger than the sum of its proper divisors (133459).

656621 is a wasteful number, since it uses less digits than its factorization.

656621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4963.

The product of its digits is 2160, while the sum is 26.

The square root of 656621 is about 810.3215411181. The cubic root of 656621 is about 86.9170389849.

The spelling of 656621 in words is "six hundred fifty-six thousand, six hundred twenty-one".