199990999 has 4 divisors (see below), whose sum is σ = 215374936. Its totient is φ = 184607064.

The previous prime is 199990993. The next prime is 199991041. The reversal of 199990999 is 999099991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 199990999 - 2³ = 199990991 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 199990999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199990991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7691949 + ... + 7691974.

It is an arithmetic number, because the mean of its divisors is an integer number (53843734).

Almost surely, 2^199990999 is an apocalyptic number.

199990999 is a deficient number, since it is larger than the sum of its proper divisors (15383937).

199990999 is a wasteful number, since it uses less digits than its factorization.

199990999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15383936.

The product of its (nonzero) digits is 4782969, while the sum is 64.

The square root of 199990999 is about 14141.8173867435. The cubic root of 199990999 is about 584.7947744831.

It can be divided in two parts, 19 and 9990999, that multiplied together give a palindrome (189828981).

The spelling of 199990999 in words is "one hundred ninety-nine million, nine hundred ninety thousand, nine hundred ninety-nine".