721170816 has 32 divisors (see below), whose sum is σ = 1915611000. Its totient is φ = 240390144.

The previous prime is 721170809. The next prime is 721170829. The reversal of 721170816 is 618071127.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 938641 + ... + 939408.

Almost surely, 2^721170816 is an apocalyptic number.

It is an amenable number.

721170816 is an abundant number, since it is smaller than the sum of its proper divisors (1194440184).

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

721170816 is a wasteful number, since it uses less digits than its factorization.

721170816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1878066 (or 1878054 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 33.

The square root of 721170816 is about 26854.6237359603. The cubic root of 721170816 is about 896.7665103201.

The spelling of 721170816 in words is "seven hundred twenty-one million, one hundred seventy thousand, eight hundred sixteen".