18712489 has 2 divisors, whose sum is σ = 18712490. Its totient is φ = 18712488.

The previous prime is 18712487. The next prime is 18712513. The reversal of 18712489 is 98421781.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14440000 + 4272489 = 3800^2 + 2067^2 .

It is an emirp because it is prime and its reverse (98421781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18712489 - 2¹ = 18712487 is a prime.

Together with 18712487, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18712483) 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, 9356244 + 9356245.

It is an arithmetic number, because the mean of its divisors is an integer number (9356245).

Almost surely, 2^18712489 is an apocalyptic number.

It is an amenable number.

18712489 is a deficient number, since it is larger than the sum of its proper divisors (1).

18712489 is an equidigital number, since it uses as much as digits as its factorization.

18712489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 40.

The square root of 18712489 is about 4325.7934532291. The cubic root of 18712489 is about 265.4873623080.

The spelling of 18712489 in words is "eighteen million, seven hundred twelve thousand, four hundred eighty-nine".