31918489 has 2 divisors, whose sum is σ = 31918490. Its totient is φ = 31918488.

The previous prime is 31918477. The next prime is 31918507. The reversal of 31918489 is 98481913.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31270464 + 648025 = 5592^2 + 805^2 .

It is an emirp because it is prime and its reverse (98481913) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31918489 - 2¹³ = 31910297 is a prime.

It is not a weakly prime, because it can be changed into another prime (31918429) 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, 15959244 + 15959245.

It is an arithmetic number, because the mean of its divisors is an integer number (15959245).

Almost surely, 2^31918489 is an apocalyptic number.

It is an amenable number.

31918489 is a deficient number, since it is larger than the sum of its proper divisors (1).

31918489 is an equidigital number, since it uses as much as digits as its factorization.

31918489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 43.

The square root of 31918489 is about 5649.6450330972. The cubic root of 31918489 is about 317.2104173416.

The spelling of 31918489 in words is "thirty-one million, nine hundred eighteen thousand, four hundred eighty-nine".