21144199 has 4 divisors (see below), whose sum is σ = 22063536. Its totient is φ = 20224864.

The previous prime is 21144187. The next prime is 21144203. The reversal of 21144199 is 99144112.

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 21144199 - 2¹³ = 21136007 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21144199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144119) 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, 459634 + ... + 459679.

It is an arithmetic number, because the mean of its divisors is an integer number (5515884).

Almost surely, 2^21144199 is an apocalyptic number.

21144199 is a deficient number, since it is larger than the sum of its proper divisors (919337).

21144199 is an equidigital number, since it uses as much as digits as its factorization.

21144199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 919336.

The product of its digits is 2592, while the sum is 31.

The square root of 21144199 is about 4598.2821792491. The cubic root of 21144199 is about 276.5224604531.

The spelling of 21144199 in words is "twenty-one million, one hundred forty-four thousand, one hundred ninety-nine".