21000199 has 4 divisors (see below), whose sum is σ = 22909320. Its totient is φ = 19091080.

The previous prime is 21000193. The next prime is 21000229. The reversal of 21000199 is 99100012.

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 21000199 - 2³ = 21000191 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000191) 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, 954544 + ... + 954565.

It is an arithmetic number, because the mean of its divisors is an integer number (5727330).

Almost surely, 2^21000199 is an apocalyptic number.

21000199 is a deficient number, since it is larger than the sum of its proper divisors (1909121).

21000199 is a wasteful number, since it uses less digits than its factorization.

21000199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1909120.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 21000199 is about 4582.5974075845. The cubic root of 21000199 is about 275.8932891051.

The spelling of 21000199 in words is "twenty-one million, one hundred ninety-nine", and thus it is an aban number.