191008139 has 4 divisors (see below), whose sum is σ = 218295024. Its totient is φ = 163721256.

The previous prime is 191008133. The next prime is 191008157. The reversal of 191008139 is 931800191.

191008139 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 191008139 - 2¹² = 191004043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191008133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13643432 + ... + 13643445.

It is an arithmetic number, because the mean of its divisors is an integer number (54573756).

Almost surely, 2^191008139 is an apocalyptic number.

191008139 is a deficient number, since it is larger than the sum of its proper divisors (27286885).

191008139 is an equidigital number, since it uses as much as digits as its factorization.

191008139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27286884.

The product of its (nonzero) digits is 1944, while the sum is 32.

The square root of 191008139 is about 13820.5694166340. The cubic root of 191008139 is about 575.9047020758.

The spelling of 191008139 in words is "one hundred ninety-one million, eight thousand, one hundred thirty-nine".