31938391 has 2 divisors, whose sum is σ = 31938392. Its totient is φ = 31938390.

The previous prime is 31938371. The next prime is 31938397. The reversal of 31938391 is 19383913.

It is a strong prime.

It is an emirp because it is prime and its reverse (19383913) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31938391 - 2¹⁷ = 31807319 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31938391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31938397) 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, 15969195 + 15969196.

It is an arithmetic number, because the mean of its divisors is an integer number (15969196).

Almost surely, 2^31938391 is an apocalyptic number.

31938391 is a deficient number, since it is larger than the sum of its proper divisors (1).

31938391 is an equidigital number, since it uses as much as digits as its factorization.

31938391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 37.

The square root of 31938391 is about 5651.4061082177. The cubic root of 31938391 is about 317.2763332652.

The spelling of 31938391 in words is "thirty-one million, nine hundred thirty-eight thousand, three hundred ninety-one".