721665272 has 16 divisors (see below), whose sum is σ = 1386126000. Its totient is φ = 352031680.

The previous prime is 721665253. The next prime is 721665293. The reversal of 721665272 is 272566127.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1099772 + ... + 1100427.

It is an arithmetic number, because the mean of its divisors is an integer number (86632875).

Almost surely, 2^721665272 is an apocalyptic number.

It is an amenable number.

721665272 is a deficient number, since it is larger than the sum of its proper divisors (664460728).

721665272 is a wasteful number, since it uses less digits than its factorization.

721665272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200246 (or 2200242 counting only the distinct ones).

The product of its digits is 70560, while the sum is 38.

The square root of 721665272 is about 26863.8283198802. The cubic root of 721665272 is about 896.9714133618.

The spelling of 721665272 in words is "seven hundred twenty-one million, six hundred sixty-five thousand, two hundred seventy-two".