721660928 has 22 divisors (see below), whose sum is σ = 1442619156. Its totient is φ = 360829952.

The previous prime is 721660871. The next prime is 721660957. The reversal of 721660928 is 829066127.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 351350 + ... + 353397.

It is an arithmetic number, because the mean of its divisors is an integer number (65573598).

Almost surely, 2^721660928 is an apocalyptic number.

It is an amenable number.

721660928 is a deficient number, since it is larger than the sum of its proper divisors (720958228).

721660928 is an equidigital number, since it uses as much as digits as its factorization.

721660928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 704767 (or 704749 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 721660928 is about 26863.7474675444. The cubic root of 721660928 is about 896.9696136116.

The spelling of 721660928 in words is "seven hundred twenty-one million, six hundred sixty thousand, nine hundred twenty-eight".