189987 has 16 divisors (see below), whose sum is σ = 295680. Its totient is φ = 106272.

The previous prime is 189983. The next prime is 189989. The reversal of 189987 is 789981.

189987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 189987 - 2² = 189983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1689 + ... + 1797.

It is an arithmetic number, because the mean of its divisors is an integer number (18480).

2¹⁸⁹⁹⁸⁷ is an apocalyptic number.

189987 is a deficient number, since it is larger than the sum of its proper divisors (105693).

189987 is a wasteful number, since it uses less digits than its factorization.

189987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202.

The product of its digits is 36288, while the sum is 42.

The square root of 189987 is about 435.8749820763. The cubic root of 189987 is about 57.4876596076.

It can be divided in two parts, 189 and 987, that added together give a triangular number (1176 = T₄₈).

The spelling of 189987 in words is "one hundred eighty-nine thousand, nine hundred eighty-seven".