621764640 has 384 divisors, whose sum is σ = 2576448000. Its totient is φ = 137023488.

The previous prime is 621764629. The next prime is 621764657. The reversal of 621764640 is 46467126.

621764640 is a `hidden beast` number, since 6 + 2 + 1 + 7 + 6 + 4 + 640 = 666.

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 = 621764595 and 621764604.

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, 876606 + ... + 877314.

It is an arithmetic number, because the mean of its divisors is an integer number (6709500).

Almost surely, 2^621764640 is an apocalyptic number.

621764640 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 621764640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1288224000).

621764640 is an abundant number, since it is smaller than the sum of its proper divisors (1954683360).

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

621764640 is a wasteful number, since it uses less digits than its factorization.

621764640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 769 (or 755 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 621764640 is about 24935.2088421172. The cubic root of 621764640 is about 853.5101169109.

The spelling of 621764640 in words is "six hundred twenty-one million, seven hundred sixty-four thousand, six hundred forty".