31986431 has 2 divisors, whose sum is σ = 31986432. Its totient is φ = 31986430.

The previous prime is 31986421. The next prime is 31986439. The reversal of 31986431 is 13468913.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31986431 is a prime.

It is a super-2 number, since 2×31986431² = 2046263536235522, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31986391 and 31986400.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31986439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15993215 + 15993216.

It is an arithmetic number, because the mean of its divisors is an integer number (15993216).

Almost surely, 2^31986431 is an apocalyptic number.

31986431 is a deficient number, since it is larger than the sum of its proper divisors (1).

31986431 is an equidigital number, since it uses as much as digits as its factorization.

31986431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 35.

The square root of 31986431 is about 5655.6547808366. The cubic root of 31986431 is about 317.4353302060.

The spelling of 31986431 in words is "thirty-one million, nine hundred eighty-six thousand, four hundred thirty-one".