31993387 has 2 divisors, whose sum is σ = 31993388. Its totient is φ = 31993386.

The previous prime is 31993373. The next prime is 31993411. The reversal of 31993387 is 78339913.

It is a weak prime.

It is an emirp because it is prime and its reverse (78339913) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31993387 - 2⁷ = 31993259 is a prime.

It is not a weakly prime, because it can be changed into another prime (31993327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15996693 + 15996694.

It is an arithmetic number, because the mean of its divisors is an integer number (15996694).

Almost surely, 2^31993387 is an apocalyptic number.

31993387 is a deficient number, since it is larger than the sum of its proper divisors (1).

31993387 is an equidigital number, since it uses as much as digits as its factorization.

31993387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 122472, while the sum is 43.

The square root of 31993387 is about 5656.2697071480. The cubic root of 31993387 is about 317.4583391304.

The spelling of 31993387 in words is "thirty-one million, nine hundred ninety-three thousand, three hundred eighty-seven".