721646616 has 64 divisors (see below), whose sum is σ = 1828753920. Its totient is φ = 237283200.

The previous prime is 721646609. The next prime is 721646659. The reversal of 721646616 is 616646127.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1121991 + ... + 1122633.

It is an arithmetic number, because the mean of its divisors is an integer number (28574280).

Almost surely, 2^721646616 is an apocalyptic number.

It is an amenable number.

721646616 is an abundant number, since it is smaller than the sum of its proper divisors (1107107304).

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

721646616 is a wasteful number, since it uses less digits than its factorization.

721646616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1216 (or 1212 counting only the distinct ones).

The product of its digits is 72576, while the sum is 39.

The square root of 721646616 is about 26863.4810849227. The cubic root of 721646616 is about 896.9636839968.

The spelling of 721646616 in words is "seven hundred twenty-one million, six hundred forty-six thousand, six hundred sixteen".