656611980 has 24 divisors (see below), whose sum is σ = 1838513712. Its totient is φ = 175096512.

The previous prime is 656611973. The next prime is 656612039. The reversal of 656611980 is 89116656.

It is a happy number.

It is a super-2 number, since 2×656611980² = 862278584559040800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5471707 + ... + 5471826.

It is an arithmetic number, because the mean of its divisors is an integer number (76604738).

Almost surely, 2^656611980 is an apocalyptic number.

656611980 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

656611980 is an abundant number, since it is smaller than the sum of its proper divisors (1181901732).

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

656611980 is a wasteful number, since it uses less digits than its factorization.

656611980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10943545 (or 10943543 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 656611980 is about 25624.4410670750. The cubic root of 656611980 is about 869.1664099010.

The spelling of 656611980 in words is "six hundred fifty-six million, six hundred eleven thousand, nine hundred eighty".