31861369 has 2 divisors, whose sum is σ = 31861370. Its totient is φ = 31861368.

The previous prime is 31861351. The next prime is 31861391. The reversal of 31861369 is 96316813.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22325625 + 9535744 = 4725^2 + 3088^2 .

It is a cyclic number.

It is not a de Polignac number, because 31861369 - 2⁷ = 31861241 is a prime.

It is a super-2 number, since 2×31861369² = 2030293669108322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31861339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15930684 + 15930685.

It is an arithmetic number, because the mean of its divisors is an integer number (15930685).

Almost surely, 2^31861369 is an apocalyptic number.

It is an amenable number.

31861369 is a deficient number, since it is larger than the sum of its proper divisors (1).

31861369 is an equidigital number, since it uses as much as digits as its factorization.

31861369 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 37.

The square root of 31861369 is about 5644.5875845805. The cubic root of 31861369 is about 317.0210821659.

It can be divided in two parts, 3186 and 1369, that multiplied together give a palindrome (4361634).

The spelling of 31861369 in words is "thirty-one million, eight hundred sixty-one thousand, three hundred sixty-nine".