656172020 has 96 divisors (see below), whose sum is σ = 1605569280. Its totient is φ = 220631040.

The previous prime is 656171993. The next prime is 656172031. The reversal of 656172020 is 20271656.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2865266 + ... + 2865494.

It is an arithmetic number, because the mean of its divisors is an integer number (16724680).

Almost surely, 2^656172020 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 656172020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (802784640).

656172020 is an abundant number, since it is smaller than the sum of its proper divisors (949397260).

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

656172020 is a wasteful number, since it uses less digits than its factorization.

656172020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553 (or 551 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 656172020 is about 25615.8548559286. The cubic root of 656172020 is about 868.9722394699.

The spelling of 656172020 in words is "six hundred fifty-six million, one hundred seventy-two thousand, twenty".