188638009 has 8 divisors (see below), whose sum is σ = 216609728. Its totient is φ = 160922160.

The previous prime is 188637991. The next prime is 188638013. The reversal of 188638009 is 900836881.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 188638009 - 2¹⁷ = 188506937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (188638049) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62382 + ... + 65335.

It is an arithmetic number, because the mean of its divisors is an integer number (27076216).

Almost surely, 2^188638009 is an apocalyptic number.

It is an amenable number.

188638009 is a deficient number, since it is larger than the sum of its proper divisors (27971719).

188638009 is a wasteful number, since it uses less digits than its factorization.

188638009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127935.

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 188638009 is about 13734.5552894879. Note that the first 3 decimals coincide. The cubic root of 188638009 is about 573.5127376709.

The spelling of 188638009 in words is "one hundred eighty-eight million, six hundred thirty-eight thousand, nine".