191171821849 has 2 divisors, whose sum is σ = 191171821850. Its totient is φ = 191171821848.

The previous prime is 191171821817. The next prime is 191171821859. The reversal of 191171821849 is 948128171191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 191171821824 + 25 = 437232^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 191171821849 - 2⁵ = 191171821817 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 191171821796 and 191171821805.

It is not a weakly prime, because it can be changed into another prime (191171821859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95585910924 + 95585910925.

It is an arithmetic number, because the mean of its divisors is an integer number (95585910925).

Almost surely, 2^191171821849 is an apocalyptic number.

It is an amenable number.

191171821849 is a deficient number, since it is larger than the sum of its proper divisors (1).

191171821849 is an equidigital number, since it uses as much as digits as its factorization.

191171821849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 290304, while the sum is 52.

The spelling of 191171821849 in words is "one hundred ninety-one billion, one hundred seventy-one million, eight hundred twenty-one thousand, eight hundred forty-nine".