190891 has 2 divisors, whose sum is σ = 190892. Its totient is φ = 190890.

The previous prime is 190889. The next prime is 190901. The reversal of 190891 is 198091.

It is a weak prime.

It is an emirp because it is prime and its reverse (198091) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 190891 - 2¹ = 190889 is a prime.

Together with 190889, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (190811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95445 + 95446.

It is an arithmetic number, because the mean of its divisors is an integer number (95446).

2¹⁹⁰⁸⁹¹ is an apocalyptic number.

190891 is a deficient number, since it is larger than the sum of its proper divisors (1).

190891 is an equidigital number, since it uses as much as digits as its factorization.

190891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 190891 is about 436.9107460340. The cubic root of 190891 is about 57.5786950207.

It can be divided in two parts, 190 and 891, that added together give a triangular number (1081 = T₄₆).

The spelling of 190891 in words is "one hundred ninety thousand, eight hundred ninety-one".