31140391 has 2 divisors, whose sum is σ = 31140392. Its totient is φ = 31140390.

The previous prime is 31140349. The next prime is 31140401. The reversal of 31140391 is 19304113.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31140391 - 2¹⁵ = 31107623 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31140331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15570195 + 15570196.

It is an arithmetic number, because the mean of its divisors is an integer number (15570196).

Almost surely, 2^31140391 is an apocalyptic number.

31140391 is a deficient number, since it is larger than the sum of its proper divisors (1).

31140391 is an equidigital number, since it uses as much as digits as its factorization.

31140391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 31140391 is about 5580.3576050286. The cubic root of 31140391 is about 314.6115679096.

The spelling of 31140391 in words is "thirty-one million, one hundred forty thousand, three hundred ninety-one".