72320657 has 4 divisors (see below), whose sum is σ = 72493680. Its totient is φ = 72147636.

The previous prime is 72320641. The next prime is 72320659. The reversal of 72320657 is 75602327.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72320657 - 2⁴ = 72320641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72320659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85883 + ... + 86720.

It is an arithmetic number, because the mean of its divisors is an integer number (18123420).

Almost surely, 2^72320657 is an apocalyptic number.

It is an amenable number.

72320657 is a deficient number, since it is larger than the sum of its proper divisors (173023).

72320657 is a wasteful number, since it uses less digits than its factorization.

72320657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173022.

The product of its (nonzero) digits is 17640, while the sum is 32.

The square root of 72320657 is about 8504.1552784506. The cubic root of 72320657 is about 416.6334365677.

The spelling of 72320657 in words is "seventy-two million, three hundred twenty thousand, six hundred fifty-seven".