656620999 has 4 divisors (see below), whose sum is σ = 656701864. Its totient is φ = 656540136.

The previous prime is 656620969. The next prime is 656621011. The reversal of 656620999 is 999026656.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 656620999 - 2¹⁹ = 656096711 is a prime.

It is a super-2 number, since 2×656620999² = 862302272655516002, 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 (656620969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26697 + ... + 45010.

It is an arithmetic number, because the mean of its divisors is an integer number (164175466).

Almost surely, 2^656620999 is an apocalyptic number.

656620999 is a deficient number, since it is larger than the sum of its proper divisors (80865).

656620999 is an equidigital number, since it uses as much as digits as its factorization.

656620999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80864.

The product of its (nonzero) digits is 1574640, while the sum is 52.

The square root of 656620999 is about 25624.6170507971. The cubic root of 656620999 is about 869.1703894080.

The spelling of 656620999 in words is "six hundred fifty-six million, six hundred twenty thousand, nine hundred ninety-nine".