189990 has 24 divisors (see below), whose sum is σ = 494208. Its totient is φ = 50640.

The previous prime is 189989. The next prime is 189997. The reversal of 189990 is 99981.

189990 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189997) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 966 + ... + 1145.

It is an arithmetic number, because the mean of its divisors is an integer number (20592).

2¹⁸⁹⁹⁹⁰ is an apocalyptic number.

189990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

189990 is an abundant number, since it is smaller than the sum of its proper divisors (304218).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

189990 is a wasteful number, since it uses less digits than its factorization.

189990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2124 (or 2121 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 189990 is about 435.8784234164. The cubic root of 189990 is about 57.4879621933.

Subtracting from 189990 its reverse (99981), we obtain a palindrome (90009).

The spelling of 189990 in words is "one hundred eighty-nine thousand, nine hundred ninety".