621991440 has 320 divisors, whose sum is σ = 2529361920. Its totient is φ = 137479680.

The previous prime is 621991439. The next prime is 621991457. The reversal of 621991440 is 44199126.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 621991395 and 621991404.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 468057 + ... + 469383.

It is an arithmetic number, because the mean of its divisors is an integer number (7904256).

Almost surely, 2^621991440 is an apocalyptic number.

621991440 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 621991440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1264680960).

621991440 is an abundant number, since it is smaller than the sum of its proper divisors (1907370480).

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

621991440 is a wasteful number, since it uses less digits than its factorization.

621991440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1387 (or 1375 counting only the distinct ones).

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

The square root of 621991440 is about 24939.7562137243. The cubic root of 621991440 is about 853.6138820925.

The spelling of 621991440 in words is "six hundred twenty-one million, nine hundred ninety-one thousand, four hundred forty".