656720 has 20 divisors (see below), whose sum is σ = 1527060. Its totient is φ = 262656.

The previous prime is 656707. The next prime is 656737. The reversal of 656720 is 27656.

It can be written as a sum of positive squares in 2 ways, for example, as 126736 + 529984 = 356^2 + 728^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-3 number, since 3×656720³ = 849692887033344000, which contains 333 as substring.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a zygodrome in base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 656720.

It is a congruent number.

It is an unprimeable number.

656720 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4025 + ... + 4184.

It is an arithmetic number, because the mean of its divisors is an integer number (76353).

2⁶⁵⁶⁷²⁰ is an apocalyptic number.

It is an amenable number.

656720 is an abundant number, since it is smaller than the sum of its proper divisors (870340).

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

656720 is a wasteful number, since it uses less digits than its factorization.

656720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8222 (or 8216 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 656720 is about 810.3826256775. The cubic root of 656720 is about 86.9214069813.

The spelling of 656720 in words is "six hundred fifty-six thousand, seven hundred twenty".