189000991 has 2 divisors, whose sum is σ = 189000992. Its totient is φ = 189000990.

The previous prime is 189000989. The next prime is 189001003. The reversal of 189000991 is 199000981.

It is a weak prime.

It is an emirp because it is prime and its reverse (199000981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 189000991 - 2¹ = 189000989 is a prime.

Together with 189000989, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 189000991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (189000901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94500495 + 94500496.

It is an arithmetic number, because the mean of its divisors is an integer number (94500496).

Almost surely, 2^189000991 is an apocalyptic number.

189000991 is a deficient number, since it is larger than the sum of its proper divisors (1).

189000991 is an equidigital number, since it uses as much as digits as its factorization.

189000991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 37.

The square root of 189000991 is about 13747.7631271418. The cubic root of 189000991 is about 573.8803578537.

It can be divided in two parts, 18 and 9000991, that added together give a palindrome (9001009).

The spelling of 189000991 in words is "one hundred eighty-nine million, nine hundred ninety-one", and thus it is an aban number.