31311321 has 4 divisors (see below), whose sum is σ = 41748432. Its totient is φ = 20874212.

The previous prime is 31311281. The next prime is 31311323. The reversal of 31311321 is 12311313.

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 31311321 - 2¹⁴ = 31294937 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31311321.

It is not an unprimeable number, because it can be changed into a prime (31311323) 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, 5218551 + ... + 5218556.

It is an arithmetic number, because the mean of its divisors is an integer number (10437108).

Almost surely, 2^31311321 is an apocalyptic number.

It is an amenable number.

31311321 is a deficient number, since it is larger than the sum of its proper divisors (10437111).

31311321 is a wasteful number, since it uses less digits than its factorization.

31311321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10437110.

The product of its digits is 54, while the sum is 15.

The square root of 31311321 is about 5595.6519727374. The cubic root of 31311321 is about 315.1861535108.

Adding to 31311321 its reverse (12311313), we get a palindrome (43622634).

The spelling of 31311321 in words is "thirty-one million, three hundred eleven thousand, three hundred twenty-one".