621606660 has 96 divisors (see below), whose sum is σ = 1881747840. Its totient is φ = 152782848.

The previous prime is 621606613. The next prime is 621606691. The reversal of 621606660 is 66606126.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34812 + ... + 49548.

It is an arithmetic number, because the mean of its divisors is an integer number (19601540).

Almost surely, 2^621606660 is an apocalyptic number.

621606660 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 621606660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (940873920).

621606660 is an abundant number, since it is smaller than the sum of its proper divisors (1260141180).

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

621606660 is a wasteful number, since it uses less digits than its factorization.

621606660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14805 (or 14803 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 33.

The square root of 621606660 is about 24932.0408310271. The cubic root of 621606660 is about 853.4378232372.

It can be divided in two parts, 6216066 and 60, that added together give a palindrome (6216126).

The spelling of 621606660 in words is "six hundred twenty-one million, six hundred six thousand, six hundred sixty".