721221616 has 20 divisors (see below), whose sum is σ = 1398754224. Its totient is φ = 360252800.

The previous prime is 721221569. The next prime is 721221629. The reversal of 721221616 is 616122127.

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, 5365 + ... + 38356.

Almost surely, 2^721221616 is an apocalyptic number.

It is an amenable number.

721221616 is a deficient number, since it is larger than the sum of its proper divisors (677532608).

721221616 is a wasteful number, since it uses less digits than its factorization.

721221616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44760 (or 44754 counting only the distinct ones).

The product of its digits is 2016, while the sum is 28.

The square root of 721221616 is about 26855.5695527017. The cubic root of 721221616 is about 896.7875662050.

The spelling of 721221616 in words is "seven hundred twenty-one million, two hundred twenty-one thousand, six hundred sixteen".