191669 has 2 divisors, whose sum is σ = 191670. Its totient is φ = 191668.

The previous prime is 191657. The next prime is 191671. The reversal of 191669 is 966191.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122500 + 69169 = 350^2 + 263^2 .

It is an emirp because it is prime and its reverse (966191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191669 - 2⁸ = 191413 is a prime.

It is a super-2 number, since 2×191669² = 73474011122, which contains 22 as substring.

Together with 191671, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95834 + 95835.

It is an arithmetic number, because the mean of its divisors is an integer number (95835).

2¹⁹¹⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

191669 is a deficient number, since it is larger than the sum of its proper divisors (1).

191669 is an equidigital number, since it uses as much as digits as its factorization.

191669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 32.

The square root of 191669 is about 437.8001827318. The cubic root of 191669 is about 57.6568120344.

The spelling of 191669 in words is "one hundred ninety-one thousand, six hundred sixty-nine".