31612381 has 2 divisors, whose sum is σ = 31612382. Its totient is φ = 31612380.

The previous prime is 31612369. The next prime is 31612391. The reversal of 31612381 is 18321613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30980356 + 632025 = 5566^2 + 795^2 .

It is a cyclic number.

It is not a de Polignac number, because 31612381 - 2⁹ = 31611869 is a prime.

It is a super-2 number, since 2×31612381² = 1998685264978322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31612351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15806190 + 15806191.

It is an arithmetic number, because the mean of its divisors is an integer number (15806191).

Almost surely, 2^31612381 is an apocalyptic number.

It is an amenable number.

31612381 is a deficient number, since it is larger than the sum of its proper divisors (1).

31612381 is an equidigital number, since it uses as much as digits as its factorization.

31612381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 25.

The square root of 31612381 is about 5622.4888617053. The cubic root of 31612381 is about 316.1931102134.

Adding to 31612381 its reverse (18321613), we get a palindrome (49933994).

The spelling of 31612381 in words is "thirty-one million, six hundred twelve thousand, three hundred eighty-one".