191355491 has 2 divisors, whose sum is σ = 191355492. Its totient is φ = 191355490.

The previous prime is 191355457. The next prime is 191355523. The reversal of 191355491 is 194553191.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191355491 is a prime.

It is not a weakly prime, because it can be changed into another prime (191355401) 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, 95677745 + 95677746.

It is an arithmetic number, because the mean of its divisors is an integer number (95677746).

Almost surely, 2^191355491 is an apocalyptic number.

191355491 is a deficient number, since it is larger than the sum of its proper divisors (1).

191355491 is an equidigital number, since it uses as much as digits as its factorization.

191355491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24300, while the sum is 38.

The square root of 191355491 is about 13833.1301952956. The cubic root of 191355491 is about 576.2535886269.

The spelling of 191355491 in words is "one hundred ninety-one million, three hundred fifty-five thousand, four hundred ninety-one".