656620998 has 64 divisors (see below), whose sum is σ = 1459399680. Its totient is φ = 195296000.

The previous prime is 656620969. The next prime is 656621011. The reversal of 656620998 is 899026656.

It is a super-2 number, since 2×656620998² = 862302270029032008, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 656620998.

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, 912883 + ... + 913601.

It is an arithmetic number, because the mean of its divisors is an integer number (22803120).

Almost surely, 2^656620998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 656620998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (729699840).

656620998 is an abundant number, since it is smaller than the sum of its proper divisors (802778682).

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

656620998 is a wasteful number, since it uses less digits than its factorization.

656620998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 973.

The product of its (nonzero) digits is 1399680, while the sum is 51.

The square root of 656620998 is about 25624.6170312846. The cubic root of 656620998 is about 869.1703889668.

The spelling of 656620998 in words is "six hundred fifty-six million, six hundred twenty thousand, nine hundred ninety-eight".