31388489 has 12 divisors (see below), whose sum is σ = 34752900. Its totient is φ = 28327200.

The previous prime is 31388479. The next prime is 31388507. The reversal of 31388489 is 98488313.

It can be written as a sum of positive squares in 2 ways, for example, as 1138489 + 30250000 = 1067^2 + 5500^2 .

It is not a de Polignac number, because 31388489 - 2⁴ = 31388473 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31388419) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17159 + ... + 18899.

It is an arithmetic number, because the mean of its divisors is an integer number (2896075).

Almost surely, 2^31388489 is an apocalyptic number.

It is an amenable number.

31388489 is a deficient number, since it is larger than the sum of its proper divisors (3364411).

31388489 is a wasteful number, since it uses less digits than its factorization.

31388489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1912 (or 1901 counting only the distinct ones).

The product of its digits is 165888, while the sum is 44.

The square root of 31388489 is about 5602.5430832792. The cubic root of 31388489 is about 315.4448707048. Note that the first 3 decimals are identical.

The spelling of 31388489 in words is "thirty-one million, three hundred eighty-eight thousand, four hundred eighty-nine".