18908189 has 4 divisors (see below), whose sum is σ = 18916956. Its totient is φ = 18899424.

The previous prime is 18908167. The next prime is 18908237. The reversal of 18908189 is 98180981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 98180981 = 2447 ⋅40123.

It can be written as a sum of positive squares in 2 ways, for example, as 4972900 + 13935289 = 2230^2 + 3733^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18908189 is a prime.

It is a super-2 number, since 2×18908189² = 715039222519442, which contains 22 as substring.

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 (18908119) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1367 + ... + 6299.

It is an arithmetic number, because the mean of its divisors is an integer number (4729239).

Almost surely, 2^18908189 is an apocalyptic number.

It is an amenable number.

18908189 is a deficient number, since it is larger than the sum of its proper divisors (8767).

18908189 is an equidigital number, since it uses as much as digits as its factorization.

18908189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8766.

The product of its (nonzero) digits is 41472, while the sum is 44.

The square root of 18908189 is about 4348.3547463380. The cubic root of 18908189 is about 266.4096661100.

The spelling of 18908189 in words is "eighteen million, nine hundred eight thousand, one hundred eighty-nine".