721893644 has 24 divisors (see below), whose sum is σ = 1357599600. Its totient is φ = 334642176.

The previous prime is 721893631. The next prime is 721893649. The reversal of 721893644 is 446398127.

It is a super-2 number, since 2×721893644² = 1042260866495197472, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 721893595 and 721893604.

It is not an unprimeable number, because it can be changed into a prime (721893649) 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, 74669 + ... + 83780.

It is an arithmetic number, because the mean of its divisors is an integer number (56566650).

Almost surely, 2^721893644 is an apocalyptic number.

It is an amenable number.

721893644 is a deficient number, since it is larger than the sum of its proper divisors (635705956).

721893644 is a wasteful number, since it uses less digits than its factorization.

721893644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158537 (or 158535 counting only the distinct ones).

The product of its digits is 290304, while the sum is 44.

The square root of 721893644 is about 26868.0785319680. The cubic root of 721893644 is about 897.0660193422.

The spelling of 721893644 in words is "seven hundred twenty-one million, eight hundred ninety-three thousand, six hundred forty-four".