199808638 has 4 divisors (see below), whose sum is σ = 299712960. Its totient is φ = 99904318.

The previous prime is 199808563. The next prime is 199808641. The reversal of 199808638 is 836808991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 836808991 = 4057 ⋅206263.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49952158 + ... + 49952161.

It is an arithmetic number, because the mean of its divisors is an integer number (74928240).

Almost surely, 2^199808638 is an apocalyptic number.

199808638 is a deficient number, since it is larger than the sum of its proper divisors (99904322).

199808638 is an equidigital number, since it uses as much as digits as its factorization.

199808638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99904321.

The product of its (nonzero) digits is 746496, while the sum is 52.

The square root of 199808638 is about 14135.3683361984. The cubic root of 199808638 is about 584.6169728302.

The spelling of 199808638 in words is "one hundred ninety-nine million, eight hundred eight thousand, six hundred thirty-eight".