21045199 has 4 divisors (see below), whose sum is σ = 24051664. Its totient is φ = 18038736.

The previous prime is 21045197. The next prime is 21045229. The reversal of 21045199 is 99154012.

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 21045199 - 2¹ = 21045197 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21045199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21045197) 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, 1503222 + ... + 1503235.

It is an arithmetic number, because the mean of its divisors is an integer number (6012916).

Almost surely, 2^21045199 is an apocalyptic number.

21045199 is a deficient number, since it is larger than the sum of its proper divisors (3006465).

21045199 is an equidigital number, since it uses as much as digits as its factorization.

21045199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3006464.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 21045199 is about 4587.5046593982. The cubic root of 21045199 is about 276.0902132808.

The spelling of 21045199 in words is "twenty-one million, forty-five thousand, one hundred ninety-nine".