621391680 has 336 divisors, whose sum is σ = 2631667584. Its totient is φ = 131051520.

The previous prime is 621391679. The next prime is 621391691. The reversal of 621391680 is 86193126.

621391680 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (336).

It is a super-2 number, since 2×621391680² = 772255239946444800, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 260895 + ... + 263265.

It is an arithmetic number, because the mean of its divisors is an integer number (7832344).

Almost surely, 2^621391680 is an apocalyptic number.

621391680 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 621391680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1315833792).

621391680 is an abundant number, since it is smaller than the sum of its proper divisors (2010275904).

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

621391680 is a wasteful number, since it uses less digits than its factorization.

621391680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2414 (or 2401 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 621391680 is about 24927.7291384514. The cubic root of 621391680 is about 853.3394259548.

The spelling of 621391680 in words is "six hundred twenty-one million, three hundred ninety-one thousand, six hundred eighty".