18942989 has 8 divisors (see below), whose sum is σ = 20680632. Its totient is φ = 17245440.

The previous prime is 18942983. The next prime is 18942997. The reversal of 18942989 is 98924981.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4182025 + 14760964 = 2045^2 + 3842^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 18942989 - 2⁸ = 18942733 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 (18942983) 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, 9032 + ... + 10929.

It is an arithmetic number, because the mean of its divisors is an integer number (2585079).

Almost surely, 2^18942989 is an apocalyptic number.

It is an amenable number.

18942989 is a deficient number, since it is larger than the sum of its proper divisors (1737643).

18942989 is a wasteful number, since it uses less digits than its factorization.

18942989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20047.

The product of its digits is 373248, while the sum is 50.

The square root of 18942989 is about 4352.3544203109. The cubic root of 18942989 is about 266.5730058228.

The spelling of 18942989 in words is "eighteen million, nine hundred forty-two thousand, nine hundred eighty-nine".