189905 has 8 divisors (see below), whose sum is σ = 240000. Its totient is φ = 143856.

The previous prime is 189901. The next prime is 189913. The reversal of 189905 is 509981.

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

It is a cyclic number.

It is not a de Polignac number, because 189905 - 2² = 189901 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (189901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 905 + ... + 1094.

It is an arithmetic number, because the mean of its divisors is an integer number (30000).

2¹⁸⁹⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

189905 is a deficient number, since it is larger than the sum of its proper divisors (50095).

189905 is a wasteful number, since it uses less digits than its factorization.

189905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2023.

The product of its (nonzero) digits is 3240, while the sum is 32.

The square root of 189905 is about 435.7809082555. The cubic root of 189905 is about 57.4793876970.

The spelling of 189905 in words is "one hundred eighty-nine thousand, nine hundred five".