199999820 has 12 divisors (see below), whose sum is σ = 419999664. Its totient is φ = 79999920.

The previous prime is 199999819. The next prime is 199999831. The reversal of 199999820 is 28999991.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4999976 + ... + 5000015.

It is an arithmetic number, because the mean of its divisors is an integer number (34999972).

Almost surely, 2^199999820 is an apocalyptic number.

199999820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

199999820 is an abundant number, since it is smaller than the sum of its proper divisors (219999844).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

199999820 is a wasteful number, since it uses less digits than its factorization.

199999820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10000000 (or 9999998 counting only the distinct ones).

The product of its (nonzero) digits is 944784, while the sum is 56.

The square root of 199999820 is about 14142.1292597685. The cubic root of 199999820 is about 584.8033722015.

The spelling of 199999820 in words is "one hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred twenty".