191208139 has 2 divisors, whose sum is σ = 191208140. Its totient is φ = 191208138.

The previous prime is 191208089. The next prime is 191208167. The reversal of 191208139 is 931802191.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 191208139 - 2¹⁹ = 190683851 is a prime.

It is not a weakly prime, because it can be changed into another prime (191208169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95604069 + 95604070.

It is an arithmetic number, because the mean of its divisors is an integer number (95604070).

Almost surely, 2^191208139 is an apocalyptic number.

191208139 is a deficient number, since it is larger than the sum of its proper divisors (1).

191208139 is an equidigital number, since it uses as much as digits as its factorization.

191208139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 34.

The square root of 191208139 is about 13827.8031154627. The cubic root of 191208139 is about 576.1056372529.

The spelling of 191208139 in words is "one hundred ninety-one million, two hundred eight thousand, one hundred thirty-nine".