188885909 has 2 divisors, whose sum is σ = 188885910. Its totient is φ = 188885908.

The previous prime is 188885899. The next prime is 188885911. The reversal of 188885909 is 909588881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137405284 + 51480625 = 11722^2 + 7175^2 .

It is a cyclic number.

It is not a de Polignac number, because 188885909 - 2¹² = 188881813 is a prime.

It is a Sophie Germain prime.

Together with 188885911, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (188881909) 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, 94442954 + 94442955.

It is an arithmetic number, because the mean of its divisors is an integer number (94442955).

Almost surely, 2^188885909 is an apocalyptic number.

It is an amenable number.

188885909 is a deficient number, since it is larger than the sum of its proper divisors (1).

188885909 is an equidigital number, since it uses as much as digits as its factorization.

188885909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1658880, while the sum is 56.

The square root of 188885909 is about 13743.5770089158. The cubic root of 188885909 is about 573.7638563333.

The spelling of 188885909 in words is "one hundred eighty-eight million, eight hundred eighty-five thousand, nine hundred nine".