18189890 has 8 divisors (see below), whose sum is σ = 32741820. Its totient is φ = 7275952.

The previous prime is 18189889. The next prime is 18189917. The reversal of 18189890 is 9898181.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18037009 + 152881 = 4247^2 + 391^2 .

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

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 909485 + ... + 909504.

Almost surely, 2^18189890 is an apocalyptic number.

18189890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18189890 is a deficient number, since it is larger than the sum of its proper divisors (14551930).

18189890 is a wasteful number, since it uses less digits than its factorization.

18189890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1818996.

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

The square root of 18189890 is about 4264.9607266656. The cubic root of 18189890 is about 262.9924964246.

The spelling of 18189890 in words is "eighteen million, one hundred eighty-nine thousand, eight hundred ninety".