189391891 has 8 divisors (see below), whose sum is σ = 204305024. Its totient is φ = 174528000.

The previous prime is 189391879. The next prime is 189391903. The reversal of 189391891 is 198193981.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (189391879) and next prime (189391903).

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 189391891 - 2⁵ = 189391859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (189391801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4110 + ... + 19891.

It is an arithmetic number, because the mean of its divisors is an integer number (25538128).

Almost surely, 2^189391891 is an apocalyptic number.

189391891 is a deficient number, since it is larger than the sum of its proper divisors (14913133).

189391891 is a wasteful number, since it uses less digits than its factorization.

189391891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24621.

The product of its digits is 139968, while the sum is 49.

The square root of 189391891 is about 13761.9726420306. The cubic root of 189391891 is about 574.2757267738.

The spelling of 189391891 in words is "one hundred eighty-nine million, three hundred ninety-one thousand, eight hundred ninety-one".