721720044 has 30 divisors (see below), whose sum is σ = 1886719604. Its totient is φ = 240573240.

The previous prime is 721720033. The next prime is 721720093. The reversal of 721720044 is 440027127.

It is a happy number.

It is a super-2 number, since 2×721720044² = 1041759643822723872, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 9 ways as a sum of consecutive naturals, for example, 1113442 + ... + 1114089.

Almost surely, 2^721720044 is an apocalyptic number.

It is an amenable number.

721720044 is an abundant number, since it is smaller than the sum of its proper divisors (1164999560).

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

721720044 is a wasteful number, since it uses less digits than its factorization.

721720044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2227547 (or 2227536 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 27.

The square root of 721720044 is about 26864.8477382620. The cubic root of 721720044 is about 896.9941051726.

It can be divided in two parts, 7217 and 20044, that added together give a triangular number (27261 = T₂₃₃).

The spelling of 721720044 in words is "seven hundred twenty-one million, seven hundred twenty thousand, forty-four".