721621626 has 16 divisors (see below), whose sum is σ = 1574447328. Its totient is φ = 218673200.

The previous prime is 721621603. The next prime is 721621633. The reversal of 721621626 is 626126127.

It is a super-2 number, since 2×721621626² = 1041475542221767752, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

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 7 ways as a sum of consecutive naturals, for example, 5466765 + ... + 5466896.

It is an arithmetic number, because the mean of its divisors is an integer number (98402958).

Almost surely, 2^721621626 is an apocalyptic number.

721621626 is an abundant number, since it is smaller than the sum of its proper divisors (852825702).

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

721621626 is a wasteful number, since it uses less digits than its factorization.

721621626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10933677.

The product of its digits is 12096, while the sum is 33.

The square root of 721621626 is about 26863.0159513038. The cubic root of 721621626 is about 896.9533301844.

The spelling of 721621626 in words is "seven hundred twenty-one million, six hundred twenty-one thousand, six hundred twenty-six".