191327921 has 2 divisors, whose sum is σ = 191327922. Its totient is φ = 191327920.

The previous prime is 191327887. The next prime is 191327977. The reversal of 191327921 is 129723191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 169937296 + 21390625 = 13036^2 + 4625^2 .

It is a cyclic number.

It is not a de Polignac number, because 191327921 - 2¹⁴ = 191311537 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (191327221) 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 as a sum of consecutive naturals, namely, 95663960 + 95663961.

It is an arithmetic number, because the mean of its divisors is an integer number (95663961).

Almost surely, 2^191327921 is an apocalyptic number.

It is an amenable number.

191327921 is a deficient number, since it is larger than the sum of its proper divisors (1).

191327921 is an equidigital number, since it uses as much as digits as its factorization.

191327921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6804, while the sum is 35.

The square root of 191327921 is about 13832.1336387413. The cubic root of 191327921 is about 576.2259122597.

The spelling of 191327921 in words is "one hundred ninety-one million, three hundred twenty-seven thousand, nine hundred twenty-one".