721665452 has 12 divisors (see below), whose sum is σ = 1266214656. Its totient is φ = 359889840.

The previous prime is 721665433. The next prime is 721665463. The reversal of 721665452 is 254566127.

It is a super-2 number, since 2×721665452² = 1041602049220728608, which contains 22 as substring.

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, 233999 + ... + 237062.

It is an arithmetic number, because the mean of its divisors is an integer number (105517888).

Almost surely, 2^721665452 is an apocalyptic number.

It is an amenable number.

721665452 is a deficient number, since it is larger than the sum of its proper divisors (544549204).

721665452 is a wasteful number, since it uses less digits than its factorization.

721665452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471448 (or 471446 counting only the distinct ones).

The product of its digits is 100800, while the sum is 38.

The square root of 721665452 is about 26863.8316701099. The cubic root of 721665452 is about 896.9714879370.

The spelling of 721665452 in words is "seven hundred twenty-one million, six hundred sixty-five thousand, four hundred fifty-two".