621643680 has 384 divisors, whose sum is σ = 2534837760. Its totient is φ = 139345920.

The previous prime is 621643669. The next prime is 621643717. The reversal of 621643680 is 86346126.

621643680 is a `hidden beast` number, since 6 + 2 + 1 + 643 + 6 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1844472 + ... + 1844808.

It is an arithmetic number, because the mean of its divisors is an integer number (6601140).

Almost surely, 2^621643680 is an apocalyptic number.

621643680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 621643680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1267418880).

621643680 is an abundant number, since it is smaller than the sum of its proper divisors (1913194080).

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

621643680 is a wasteful number, since it uses less digits than its factorization.

621643680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429 (or 415 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 621643680 is about 24932.7832381385. The cubic root of 621643680 is about 853.4547651627.

The spelling of 621643680 in words is "six hundred twenty-one million, six hundred forty-three thousand, six hundred eighty".