72321157 has 4 divisors (see below), whose sum is σ = 74815020. Its totient is φ = 69827296.

The previous prime is 72321143. The next prime is 72321167. The reversal of 72321157 is 75112327.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43441281 + 28879876 = 6591^2 + 5374^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72321157 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 (72321167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1246888 + ... + 1246945.

It is an arithmetic number, because the mean of its divisors is an integer number (18703755).

Almost surely, 2^72321157 is an apocalyptic number.

It is an amenable number.

72321157 is a deficient number, since it is larger than the sum of its proper divisors (2493863).

72321157 is a wasteful number, since it uses less digits than its factorization.

72321157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2493862.

The product of its digits is 2940, while the sum is 28.

The square root of 72321157 is about 8504.1846757934. The cubic root of 72321157 is about 416.6343967186.

The spelling of 72321157 in words is "seventy-two million, three hundred twenty-one thousand, one hundred fifty-seven".