199820921 has 8 divisors (see below), whose sum is σ = 205365888. Its totient is φ = 194308000.

The previous prime is 199820917. The next prime is 199820983. The reversal of 199820921 is 129028991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 199820921 - 2² = 199820917 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199820821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4916 + ... + 20586.

It is an arithmetic number, because the mean of its divisors is an integer number (25670736).

Almost surely, 2^199820921 is an apocalyptic number.

It is an amenable number.

199820921 is a deficient number, since it is larger than the sum of its proper divisors (5544967).

199820921 is a wasteful number, since it uses less digits than its factorization.

199820921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16023.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 199820921 is about 14135.8028070570. The cubic root of 199820921 is about 584.6289521307.

The spelling of 199820921 in words is "one hundred ninety-nine million, eight hundred twenty thousand, nine hundred twenty-one".