31112281 has 2 divisors, whose sum is σ = 31112282. Its totient is φ = 31112280.

The previous prime is 31112209. The next prime is 31112287. The reversal of 31112281 is 18221113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30702681 + 409600 = 5541^2 + 640^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31112281 is a prime.

It is a super-2 number, since 2×31112281² = 1935948058045922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31112287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15556140 + 15556141.

It is an arithmetic number, because the mean of its divisors is an integer number (15556141).

Almost surely, 2^31112281 is an apocalyptic number.

It is an amenable number.

31112281 is a deficient number, since it is larger than the sum of its proper divisors (1).

31112281 is an equidigital number, since it uses as much as digits as its factorization.

31112281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 19.

The square root of 31112281 is about 5577.8383805915. The cubic root of 31112281 is about 314.5168742415.

Adding to 31112281 its reverse (18221113), we get a palindrome (49333394).

The spelling of 31112281 in words is "thirty-one million, one hundred twelve thousand, two hundred eighty-one".