721624660 has 24 divisors (see below), whose sum is σ = 1521184896. Its totient is φ = 287550240.

The previous prime is 721624649. The next prime is 721624669. The reversal of 721624660 is 66426127.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721624669) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 63336 + ... + 73855.

It is an arithmetic number, because the mean of its divisors is an integer number (63382704).

Almost surely, 2^721624660 is an apocalyptic number.

It is an amenable number.

721624660 is an abundant number, since it is smaller than the sum of its proper divisors (799560236).

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

721624660 is a wasteful number, since it uses less digits than its factorization.

721624660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137463 (or 137461 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 34.

The square root of 721624660 is about 26863.0724229378. The cubic root of 721624660 is about 896.9545872386.

The spelling of 721624660 in words is "seven hundred twenty-one million, six hundred twenty-four thousand, six hundred sixty".