655640980 has 72 divisors (see below), whose sum is σ = 1474744320. Its totient is φ = 244762560.

The previous prime is 655640977. The next prime is 655641031. The reversal of 655640980 is 89046556.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 511981 + ... + 513259.

It is an arithmetic number, because the mean of its divisors is an integer number (20482560).

Almost surely, 2^655640980 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 655640980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (737372160).

655640980 is an abundant number, since it is smaller than the sum of its proper divisors (819103340).

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

655640980 is a wasteful number, since it uses less digits than its factorization.

655640980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1397 (or 1376 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 43.

The square root of 655640980 is about 25605.4873025295. The cubic root of 655640980 is about 868.7377564653.

The spelling of 655640980 in words is "six hundred fifty-five million, six hundred forty thousand, nine hundred eighty".