191940839 has 2 divisors, whose sum is σ = 191940840. Its totient is φ = 191940838.

The previous prime is 191940811. The next prime is 191940841. The reversal of 191940839 is 938049191.

It is a strong prime.

It is an emirp because it is prime and its reverse (938049191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191940839 - 2²⁴ = 175163623 is a prime.

Together with 191940841, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 191940839.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191940439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95970419 + 95970420.

It is an arithmetic number, because the mean of its divisors is an integer number (95970420).

Almost surely, 2^191940839 is an apocalyptic number.

191940839 is a deficient number, since it is larger than the sum of its proper divisors (1).

191940839 is an equidigital number, since it uses as much as digits as its factorization.

191940839 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 191940839 is about 13854.2715073727. The cubic root of 191940839 is about 576.8405686146.

The spelling of 191940839 in words is "one hundred ninety-one million, nine hundred forty thousand, eight hundred thirty-nine".