191930789 has 2 divisors, whose sum is σ = 191930790. Its totient is φ = 191930788.

The previous prime is 191930779. The next prime is 191930873. The reversal of 191930789 is 987039191.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 107474689 + 84456100 = 10367^2 + 9190^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191930789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191930719) 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, 95965394 + 95965395.

It is an arithmetic number, because the mean of its divisors is an integer number (95965395).

Almost surely, 2^191930789 is an apocalyptic number.

It is an amenable number.

191930789 is a deficient number, since it is larger than the sum of its proper divisors (1).

191930789 is an equidigital number, since it uses as much as digits as its factorization.

191930789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 122472, while the sum is 47.

The square root of 191930789 is about 13853.9087986027. The cubic root of 191930789 is about 576.8305006705.

The spelling of 191930789 in words is "one hundred ninety-one million, nine hundred thirty thousand, seven hundred eighty-nine".