189188991 has 24 divisors (see below), whose sum is σ = 277739280. Its totient is φ = 124080000.

The previous prime is 189188981. The next prime is 189189041. The reversal of 189188991 is 199881981.

It is not a de Polignac number, because 189188991 - 2⁶ = 189188927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189188921) 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, 200581 + ... + 201521.

It is an arithmetic number, because the mean of its divisors is an integer number (11572470).

Almost surely, 2^189188991 is an apocalyptic number.

189188991 is a deficient number, since it is larger than the sum of its proper divisors (88550289).

189188991 is a wasteful number, since it uses less digits than its factorization.

189188991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1287 (or 1284 counting only the distinct ones).

The product of its digits is 373248, while the sum is 54.

The square root of 189188991 is about 13754.5989036395. The cubic root of 189188991 is about 574.0705751179.

The spelling of 189188991 in words is "one hundred eighty-nine million, one hundred eighty-eight thousand, nine hundred ninety-one".