189905887 has 4 divisors (see below), whose sum is σ = 191043216. Its totient is φ = 188768560.

The previous prime is 189905873. The next prime is 189905953. The reversal of 189905887 is 788509981.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 189905887 - 2²⁷ = 55688159 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 (189905857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 568414 + ... + 568747.

It is an arithmetic number, because the mean of its divisors is an integer number (47760804).

Almost surely, 2^189905887 is an apocalyptic number.

189905887 is a deficient number, since it is larger than the sum of its proper divisors (1137329).

189905887 is a wasteful number, since it uses less digits than its factorization.

189905887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1137328.

The product of its (nonzero) digits is 1451520, while the sum is 55.

The square root of 189905887 is about 13780.6344919238. The cubic root of 189905887 is about 574.7947718756.

The spelling of 189905887 in words is "one hundred eighty-nine million, nine hundred five thousand, eight hundred eighty-seven".