721108816 has 40 divisors (see below), whose sum is σ = 1430682984. Its totient is φ = 351989760.

The previous prime is 721108813. The next prime is 721108823. The reversal of 721108816 is 618801127.

It can be written as a sum of positive squares in 4 ways, for example, as 118897216 + 602211600 = 10904^2 + 24540^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721108813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131016 + ... + 136408.

Almost surely, 2^721108816 is an apocalyptic number.

It is an amenable number.

721108816 is a deficient number, since it is larger than the sum of its proper divisors (709574168).

721108816 is a wasteful number, since it uses less digits than its factorization.

721108816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5599 (or 5593 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 34.

The square root of 721108816 is about 26853.4693475536. The cubic root of 721108816 is about 896.7408108529.

The spelling of 721108816 in words is "seven hundred twenty-one million, one hundred eight thousand, eight hundred sixteen".