656400220 has 96 divisors (see below), whose sum is σ = 1730534400. Its totient is φ = 203917824.

The previous prime is 656400149. The next prime is 656400221. The reversal of 656400220 is 22004656.

It is a super-2 number, since 2×656400220² = 861722497632096800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656400221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 55816 + ... + 66544.

It is an arithmetic number, because the mean of its divisors is an integer number (18026400).

Almost surely, 2^656400220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 656400220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (865267200).

656400220 is an abundant number, since it is smaller than the sum of its proper divisors (1074134180).

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

656400220 is a wasteful number, since it uses less digits than its factorization.

656400220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10787 (or 10785 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 656400220 is about 25620.3087413091. The cubic root of 656400220 is about 869.0729633023.

Adding to 656400220 its reverse (22004656), we get a palindrome (678404876).

The spelling of 656400220 in words is "six hundred fifty-six million, four hundred thousand, two hundred twenty".