191979213 has 4 divisors (see below), whose sum is σ = 255972288. Its totient is φ = 127986140.

The previous prime is 191979209. The next prime is 191979239. The reversal of 191979213 is 312979191.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 191979213 - 2² = 191979209 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191979253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31996533 + ... + 31996538.

It is an arithmetic number, because the mean of its divisors is an integer number (63993072).

Almost surely, 2^191979213 is an apocalyptic number.

It is an amenable number.

191979213 is a deficient number, since it is larger than the sum of its proper divisors (63993075).

191979213 is an equidigital number, since it uses as much as digits as its factorization.

191979213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63993074.

The product of its digits is 30618, while the sum is 42.

The square root of 191979213 is about 13855.6563539949. The cubic root of 191979213 is about 576.8790078981.

The spelling of 191979213 in words is "one hundred ninety-one million, nine hundred seventy-nine thousand, two hundred thirteen".