31120231 has 2 divisors, whose sum is σ = 31120232. Its totient is φ = 31120230.

The previous prime is 31120213. The next prime is 31120247. The reversal of 31120231 is 13202113.

Together with previous prime (31120213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is an emirp because it is prime and its reverse (13202113) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31120231 is a prime.

It is a super-2 number, since 2×31120231² = 1936937554986722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31120211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15560115 + 15560116.

It is an arithmetic number, because the mean of its divisors is an integer number (15560116).

Almost surely, 2^31120231 is an apocalyptic number.

31120231 is a deficient number, since it is larger than the sum of its proper divisors (1).

31120231 is an equidigital number, since it uses as much as digits as its factorization.

31120231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 31120231 is about 5578.5509767322. The cubic root of 31120231 is about 314.5436610507.

Adding to 31120231 its reverse (13202113), we get a palindrome (44322344).

The spelling of 31120231 in words is "thirty-one million, one hundred twenty thousand, two hundred thirty-one".