189999999 has 60 divisors (see below), whose sum is σ = 333207864. Its totient is φ = 108020304.

The previous prime is 189999989. The next prime is 190000003. The reversal of 189999999 is 999999981.

It is a happy number.

It is not a de Polignac number, because 189999999 - 2⁴ = 189999983 is a prime.

189999999 is a modest number, since divided by 99999 gives 1899 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189999949) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 964369 + ... + 964565.

Almost surely, 2^189999999 is an apocalyptic number.

189999999 is a deficient number, since it is larger than the sum of its proper divisors (143207865).

189999999 is an frugal number, since it uses more digits than its factorization.

189999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238 (or 207 counting only the distinct ones).

The product of its digits is 38263752, while the sum is 72.

The square root of 189999999 is about 13784.0487158164. The cubic root of 189999999 is about 574.8897068859.

The spelling of 189999999 in words is "one hundred eighty-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".