656565220 has 24 divisors (see below), whose sum is σ = 1426332600. Its totient is φ = 253569792.

The previous prime is 656565209. The next prime is 656565223. The reversal of 656565220 is 22565656.

It can be written as a sum of positive squares in 4 ways, for example, as 2842596 + 653722624 = 1686^2 + 25568^2 .

It is a super-2 number, since 2×656565220² = 862155776227296800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 656565220.

It is not an unprimeable number, because it can be changed into a prime (656565223) 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, 565425 + ... + 566584.

It is an arithmetic number, because the mean of its divisors is an integer number (59430525).

Almost surely, 2^656565220 is an apocalyptic number.

It is an amenable number.

656565220 is an abundant number, since it is smaller than the sum of its proper divisors (769767380).

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

656565220 is a wasteful number, since it uses less digits than its factorization.

656565220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1132047 (or 1132045 counting only the distinct ones).

The product of its (nonzero) digits is 108000, while the sum is 37.

The square root of 656565220 is about 25623.5286406849. The cubic root of 656565220 is about 869.1457771237.

It can be divided in two parts, 65656 and 5220, that added together give a triangular number (70876 = T₃₇₆).

The spelling of 656565220 in words is "six hundred fifty-six million, five hundred sixty-five thousand, two hundred twenty".