31320321 has 4 divisors (see below), whose sum is σ = 41760432. Its totient is φ = 20880212.

The previous prime is 31320281. The next prime is 31320337. The reversal of 31320321 is 12302313.

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 31320321 - 2⁷ = 31320193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31320321.

It is not an unprimeable number, because it can be changed into a prime (31320391) 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 3 ways as a sum of consecutive naturals, for example, 5220051 + ... + 5220056.

It is an arithmetic number, because the mean of its divisors is an integer number (10440108).

Almost surely, 2^31320321 is an apocalyptic number.

It is an amenable number.

31320321 is a deficient number, since it is larger than the sum of its proper divisors (10440111).

31320321 is a wasteful number, since it uses less digits than its factorization.

31320321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10440110.

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 31320321 is about 5596.4561107901. The cubic root of 31320321 is about 315.2163492308.

Adding to 31320321 its reverse (12302313), we get a palindrome (43622634).

The spelling of 31320321 in words is "thirty-one million, three hundred twenty thousand, three hundred twenty-one".