320728631 has 4 divisors (see below), whose sum is σ = 323904264. Its totient is φ = 317553000.

The previous prime is 320728627. The next prime is 320728633. The reversal of 320728631 is 136827023.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 320728631 - 2² = 320728627 is a prime.

It is a super-2 number, since 2×320728631² = 205733709486268322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (320728633) 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, 1587665 + ... + 1587866.

It is an arithmetic number, because the mean of its divisors is an integer number (80976066).

Almost surely, 2^320728631 is an apocalyptic number.

320728631 is a deficient number, since it is larger than the sum of its proper divisors (3175633).

320728631 is a wasteful number, since it uses less digits than its factorization.

320728631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3175632.

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 320728631 is about 17908.8980956395. The cubic root of 320728631 is about 684.5091274292.

The spelling of 320728631 in words is "three hundred twenty million, seven hundred twenty-eight thousand, six hundred thirty-one".