31989889 has 2 divisors, whose sum is σ = 31989890. Its totient is φ = 31989888.

The previous prime is 31989857. The next prime is 31989907. The reversal of 31989889 is 98898913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31449664 + 540225 = 5608^2 + 735^2 .

It is a cyclic number.

It is not a de Polignac number, because 31989889 - 2⁵ = 31989857 is a prime.

It is not a weakly prime, because it can be changed into another prime (31989809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15994944 + 15994945.

It is an arithmetic number, because the mean of its divisors is an integer number (15994945).

Almost surely, 2^31989889 is an apocalyptic number.

It is an amenable number.

31989889 is a deficient number, since it is larger than the sum of its proper divisors (1).

31989889 is an equidigital number, since it uses as much as digits as its factorization.

31989889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1119744, while the sum is 55.

The square root of 31989889 is about 5655.9604843033. The cubic root of 31989889 is about 317.4467689295.

The spelling of 31989889 in words is "thirty-one million, nine hundred eighty-nine thousand, eight hundred eighty-nine".