721572157 has 16 divisors (see below), whose sum is σ = 783544752. Its totient is φ = 661939200.

The previous prime is 721572119. The next prime is 721572197. The reversal of 721572157 is 751275127.

It can be written as a sum of positive squares in 8 ways, for example, as 36650916 + 684921241 = 6054^2 + 26171^2 .

It is not a de Polignac number, because 721572157 - 2¹⁵ = 721539389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721572107) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 138907 + ... + 144007.

It is an arithmetic number, because the mean of its divisors is an integer number (48971547).

Almost surely, 2^721572157 is an apocalyptic number.

It is an amenable number.

721572157 is a deficient number, since it is larger than the sum of its proper divisors (61972595).

721572157 is a wasteful number, since it uses less digits than its factorization.

721572157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5328.

The product of its digits is 34300, while the sum is 37.

The square root of 721572157 is about 26862.0951714493. The cubic root of 721572157 is about 896.9328335711.

The spelling of 721572157 in words is "seven hundred twenty-one million, five hundred seventy-two thousand, one hundred fifty-seven".