31431889 has 4 divisors (see below), whose sum is σ = 31443300. Its totient is φ = 31420480.

The previous prime is 31431859. The next prime is 31431893. The reversal of 31431889 is 98813413.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 28569025 + 2862864 = 5345^2 + 1692^2 .

It is a cyclic number.

It is not a de Polignac number, because 31431889 - 2⁵ = 31431857 is a prime.

It is a super-2 number, since 2×31431889² = 1975927292216642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31431859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1269 + ... + 8029.

It is an arithmetic number, because the mean of its divisors is an integer number (7860825).

Almost surely, 2^31431889 is an apocalyptic number.

It is an amenable number.

31431889 is a deficient number, since it is larger than the sum of its proper divisors (11411).

31431889 is an equidigital number, since it uses as much as digits as its factorization.

31431889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11410.

The product of its digits is 20736, while the sum is 37.

The square root of 31431889 is about 5606.4149864240. The cubic root of 31431889 is about 315.5901893968.

The spelling of 31431889 in words is "thirty-one million, four hundred thirty-one thousand, eight hundred eighty-nine".