191961823 has 4 divisors (see below), whose sum is σ = 192299760. Its totient is φ = 191623888.

The previous prime is 191961811. The next prime is 191961871. The reversal of 191961823 is 328169191.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191961823 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 (191961893) 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, 168115 + ... + 169252.

It is an arithmetic number, because the mean of its divisors is an integer number (48074940).

Almost surely, 2^191961823 is an apocalyptic number.

191961823 is a deficient number, since it is larger than the sum of its proper divisors (337937).

191961823 is an equidigital number, since it uses as much as digits as its factorization.

191961823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337936.

The product of its digits is 23328, while the sum is 40.

The square root of 191961823 is about 13855.0287982378. The cubic root of 191961823 is about 576.8615889482.

The spelling of 191961823 in words is "one hundred ninety-one million, nine hundred sixty-one thousand, eight hundred twenty-three".