31897399 has 2 divisors, whose sum is σ = 31897400. Its totient is φ = 31897398.

The previous prime is 31897373. The next prime is 31897403. The reversal of 31897399 is 99379813.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31897399 - 2²³ = 23508791 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 (31897309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15948699 + 15948700.

It is an arithmetic number, because the mean of its divisors is an integer number (15948700).

Almost surely, 2^31897399 is an apocalyptic number.

31897399 is a deficient number, since it is larger than the sum of its proper divisors (1).

31897399 is an equidigital number, since it uses as much as digits as its factorization.

31897399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 367416, while the sum is 49.

The square root of 31897399 is about 5647.7782357313. The cubic root of 31897399 is about 317.1405368230.

The spelling of 31897399 in words is "thirty-one million, eight hundred ninety-seven thousand, three hundred ninety-nine".