31612981 has 2 divisors, whose sum is σ = 31612982. Its totient is φ = 31612980.

The previous prime is 31612969. The next prime is 31612991. The reversal of 31612981 is 18921613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31460881 + 152100 = 5609^2 + 390^2 .

It is an emirp because it is prime and its reverse (18921613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31612981 - 2⁷ = 31612853 is a prime.

It is a super-2 number, since 2×31612981² = 1998761135412722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31612951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15806490 + 15806491.

It is an arithmetic number, because the mean of its divisors is an integer number (15806491).

Almost surely, 2^31612981 is an apocalyptic number.

It is an amenable number.

31612981 is a deficient number, since it is larger than the sum of its proper divisors (1).

31612981 is an equidigital number, since it uses as much as digits as its factorization.

31612981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 31612981 is about 5622.5422186054. The cubic root of 31612981 is about 316.1951106392.

The spelling of 31612981 in words is "thirty-one million, six hundred twelve thousand, nine hundred eighty-one".