199991908 has 6 divisors (see below), whose sum is σ = 349985846. Its totient is φ = 99995952.

The previous prime is 199991837. The next prime is 199991941. The reversal of 199991908 is 809199991.

It can be written as a sum of positive squares in only one way, i.e., 183927844 + 16064064 = 13562^2 + 4008^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 24998985 + ... + 24998992.

Almost surely, 2^199991908 is an apocalyptic number.

It is an amenable number.

199991908 is a deficient number, since it is larger than the sum of its proper divisors (149993938).

199991908 is a wasteful number, since it uses less digits than its factorization.

199991908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49997981 (or 49997979 counting only the distinct ones).

The product of its (nonzero) digits is 472392, while the sum is 55.

The square root of 199991908 is about 14141.8495254334. The cubic root of 199991908 is about 584.7956604857.

The spelling of 199991908 in words is "one hundred ninety-nine million, nine hundred ninety-one thousand, nine hundred eight".