191398879 has 4 divisors (see below), whose sum is σ = 218741584. Its totient is φ = 164056176.

The previous prime is 191398873. The next prime is 191398897. The reversal of 191398879 is 978893191.

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 191398879 - 2¹³ = 191390687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191398873) 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, 13671342 + ... + 13671355.

It is an arithmetic number, because the mean of its divisors is an integer number (54685396).

Almost surely, 2^191398879 is an apocalyptic number.

191398879 is a deficient number, since it is larger than the sum of its proper divisors (27342705).

191398879 is an equidigital number, since it uses as much as digits as its factorization.

191398879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27342704.

The product of its digits is 979776, while the sum is 55.

The square root of 191398879 is about 13834.6983704019. The cubic root of 191398879 is about 576.2971386380.

The spelling of 191398879 in words is "one hundred ninety-one million, three hundred ninety-eight thousand, eight hundred seventy-nine".