721715157 has 16 divisors (see below), whose sum is σ = 1083857280. Its totient is φ = 474551136.

The previous prime is 721715149. The next prime is 721715191. The reversal of 721715157 is 751517127.

721715157 is a `hidden beast` number, since 72 + 1 + 71 + 515 + 7 = 666.

It is not a de Polignac number, because 721715157 - 2³ = 721715149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721715117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 181113 + ... + 185054.

It is an arithmetic number, because the mean of its divisors is an integer number (67741080).

Almost surely, 2^721715157 is an apocalyptic number.

It is an amenable number.

721715157 is a deficient number, since it is larger than the sum of its proper divisors (362142123).

721715157 is a wasteful number, since it uses less digits than its factorization.

721715157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366249 (or 366243 counting only the distinct ones).

The product of its digits is 17150, while the sum is 36.

The square root of 721715157 is about 26864.7567828186. The cubic root of 721715157 is about 896.9920805556.

The spelling of 721715157 in words is "seven hundred twenty-one million, seven hundred fifteen thousand, one hundred fifty-seven".