18649989 has 12 divisors (see below), whose sum is σ = 27059500. Its totient is φ = 12377664.

The previous prime is 18649979. The next prime is 18650041. The reversal of 18649989 is 98994681.

It can be written as a sum of positive squares in 2 ways, for example, as 16524225 + 2125764 = 4065^2 + 1458^2 .

It is not a de Polignac number, because 18649989 - 2⁴ = 18649973 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18649909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2464 + ... + 6585.

Almost surely, 2^18649989 is an apocalyptic number.

It is an amenable number.

18649989 is a deficient number, since it is larger than the sum of its proper divisors (8409511).

18649989 is a wasteful number, since it uses less digits than its factorization.

18649989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9284 (or 9281 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 54.

The square root of 18649989 is about 4318.5633027663. The cubic root of 18649989 is about 265.1914553323.

The spelling of 18649989 in words is "eighteen million, six hundred forty-nine thousand, nine hundred eighty-nine".