18497989 has 8 divisors (see below), whose sum is σ = 19637208. Its totient is φ = 17364480.

The previous prime is 18497977. The next prime is 18497993. The reversal of 18497989 is 98979481.

It can be written as a sum of positive squares in 4 ways, for example, as 2377764 + 16120225 = 1542^2 + 4015^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18497989 - 2⁷ = 18497861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18497939) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6579 + ... + 8959.

It is an arithmetic number, because the mean of its divisors is an integer number (2454651).

Almost surely, 2^18497989 is an apocalyptic number.

It is an amenable number.

18497989 is a deficient number, since it is larger than the sum of its proper divisors (1139219).

18497989 is a wasteful number, since it uses less digits than its factorization.

18497989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2855.

The product of its digits is 1306368, while the sum is 55.

The square root of 18497989 is about 4300.9288531665. The cubic root of 18497989 is about 264.4690401071.

The spelling of 18497989 in words is "eighteen million, four hundred ninety-seven thousand, nine hundred eighty-nine".