31311121 has 2 divisors, whose sum is σ = 31311122. Its totient is φ = 31311120.

The previous prime is 31311113. The next prime is 31311131. The reversal of 31311121 is 12111313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23386896 + 7924225 = 4836^2 + 2815^2 .

It is an emirp because it is prime and its reverse (12111313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31311121 - 2³ = 31311113 is a prime.

It is not a weakly prime, because it can be changed into another prime (31311101) 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 as a sum of consecutive naturals, namely, 15655560 + 15655561.

It is an arithmetic number, because the mean of its divisors is an integer number (15655561).

Almost surely, 2^31311121 is an apocalyptic number.

It is an amenable number.

31311121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31311121 is an equidigital number, since it uses as much as digits as its factorization.

31311121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18, while the sum is 13.

The square root of 31311121 is about 5595.6341016904. The cubic root of 31311121 is about 315.1854824291.

Adding to 31311121 its reverse (12111313), we get a palindrome (43422434).

The spelling of 31311121 in words is "thirty-one million, three hundred eleven thousand, one hundred twenty-one".