191666441 has 2 divisors, whose sum is σ = 191666442. Its totient is φ = 191666440.

The previous prime is 191666413. The next prime is 191666473. The reversal of 191666441 is 144666191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 190992400 + 674041 = 13820^2 + 821^2 .

It is an emirp because it is prime and its reverse (144666191) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191666441 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 191666395 and 191666404.

It is not a weakly prime, because it can be changed into another prime (191656441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95833220 + 95833221.

It is an arithmetic number, because the mean of its divisors is an integer number (95833221).

Almost surely, 2^191666441 is an apocalyptic number.

It is an amenable number.

191666441 is a deficient number, since it is larger than the sum of its proper divisors (1).

191666441 is an equidigital number, since it uses as much as digits as its factorization.

191666441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 38.

The square root of 191666441 is about 13844.3649547388. The cubic root of 191666441 is about 576.5655543853.

The spelling of 191666441 in words is "one hundred ninety-one million, six hundred sixty-six thousand, four hundred forty-one".