189539991 has 24 divisors (see below), whose sum is σ = 290862000. Its totient is φ = 118599552.

The previous prime is 189539989. The next prime is 189540017. The reversal of 189539991 is 199935981.

189539991 is a `hidden beast` number, since 18 + 9 + 539 + 9 + 91 = 666.

189539991 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 189539991 - 2¹ = 189539989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189539951) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13555 + ... + 23723.

It is an arithmetic number, because the mean of its divisors is an integer number (12119250).

Almost surely, 2^189539991 is an apocalyptic number.

189539991 is a deficient number, since it is larger than the sum of its proper divisors (101322009).

189539991 is a wasteful number, since it uses less digits than its factorization.

189539991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10303 (or 10300 counting only the distinct ones).

The product of its digits is 787320, while the sum is 54.

The square root of 189539991 is about 13767.3523598403. The cubic root of 189539991 is about 574.4253778055.

The spelling of 189539991 in words is "one hundred eighty-nine million, five hundred thirty-nine thousand, nine hundred ninety-one".