31131229 has 2 divisors, whose sum is σ = 31131230. Its totient is φ = 31131228.

The previous prime is 31131227. The next prime is 31131251. The reversal of 31131229 is 92213113.

It is an a-pointer prime, because the next prime (31131251) can be obtained adding 31131229 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31058329 + 72900 = 5573^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 31131229 - 2¹ = 31131227 is a prime.

Together with 31131227, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31131227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15565614 + 15565615.

It is an arithmetic number, because the mean of its divisors is an integer number (15565615).

Almost surely, 2^31131229 is an apocalyptic number.

It is an amenable number.

31131229 is a deficient number, since it is larger than the sum of its proper divisors (1).

31131229 is an equidigital number, since it uses as much as digits as its factorization.

31131229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 324, while the sum is 22.

The square root of 31131229 is about 5579.5366295061. The cubic root of 31131229 is about 314.5807103018.

The spelling of 31131229 in words is "thirty-one million, one hundred thirty-one thousand, two hundred twenty-nine".