191870089 has 2 divisors, whose sum is σ = 191870090. Its totient is φ = 191870088.

The previous prime is 191870087. The next prime is 191870137. The reversal of 191870089 is 980078191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154256400 + 37613689 = 12420^2 + 6133^2 .

It is an emirp because it is prime and its reverse (980078191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191870089 - 2¹ = 191870087 is a prime.

Together with 191870087, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (191870087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95935044 + 95935045.

It is an arithmetic number, because the mean of its divisors is an integer number (95935045).

Almost surely, 2^191870089 is an apocalyptic number.

It is an amenable number.

191870089 is a deficient number, since it is larger than the sum of its proper divisors (1).

191870089 is an equidigital number, since it uses as much as digits as its factorization.

191870089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 43.

The square root of 191870089 is about 13851.7179078986. The cubic root of 191870089 is about 576.7696848189.

The spelling of 191870089 in words is "one hundred ninety-one million, eight hundred seventy thousand, eighty-nine".