621664520 has 32 divisors (see below), whose sum is σ = 1401067800. Its totient is φ = 248252928.

The previous prime is 621664457. The next prime is 621664529. The reversal of 621664520 is 25466126.

It can be written as a sum of positive squares in 4 ways, for example, as 492751204 + 128913316 = 22198^2 + 11354^2 .

It is not an unprimeable number, because it can be changed into a prime (621664529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12086 + ... + 37274.

Almost surely, 2^621664520 is an apocalyptic number.

It is an amenable number.

621664520 is an abundant number, since it is smaller than the sum of its proper divisors (779403280).

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

621664520 is a wasteful number, since it uses less digits than its factorization.

621664520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25817 (or 25813 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 621664520 is about 24933.2011582949. The cubic root of 621664520 is about 853.4643021365.

The spelling of 621664520 in words is "six hundred twenty-one million, six hundred sixty-four thousand, five hundred twenty".