721116165 has 64 divisors (see below), whose sum is σ = 1442875392. Its totient is φ = 298771200.

The previous prime is 721116157. The next prime is 721116169. The reversal of 721116165 is 561611127.

It is not a de Polignac number, because 721116165 - 2³ = 721116157 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721116169) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 485514 + ... + 486996.

It is an arithmetic number, because the mean of its divisors is an integer number (22544928).

Almost surely, 2^721116165 is an apocalyptic number.

It is an amenable number.

721116165 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

721116165 is a wasteful number, since it uses less digits than its factorization.

721116165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1930.

The product of its digits is 2520, while the sum is 30.

The square root of 721116165 is about 26853.6061824106. The cubic root of 721116165 is about 896.7438571457.

It can be divided in two parts, 721 and 116165, that added together give a triangular number (116886 = T₄₈₃).

The spelling of 721116165 in words is "seven hundred twenty-one million, one hundred sixteen thousand, one hundred sixty-five".