194393809 has 2 divisors, whose sum is σ = 194393810. Its totient is φ = 194393808.

The previous prime is 194393767. The next prime is 194393813. The reversal of 194393809 is 908393491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160579584 + 33814225 = 12672^2 + 5815^2 .

It is a cyclic number.

It is not a de Polignac number, because 194393809 - 2⁷ = 194393681 is a prime.

It is not a weakly prime, because it can be changed into another prime (194393869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97196904 + 97196905.

It is an arithmetic number, because the mean of its divisors is an integer number (97196905).

Almost surely, 2^194393809 is an apocalyptic number.

It is an amenable number.

194393809 is a deficient number, since it is larger than the sum of its proper divisors (1).

194393809 is an equidigital number, since it uses as much as digits as its factorization.

194393809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 194393809 is about 13942.5180293948. The cubic root of 194393809 is about 579.2874811664.

The spelling of 194393809 in words is "one hundred ninety-four million, three hundred ninety-three thousand, eight hundred nine".