21230205 has 16 divisors (see below), whose sum is σ = 34219584. Its totient is φ = 11239040.

The previous prime is 21230203. The next prime is 21230213. The reversal of 21230205 is 50203212.

It is not a de Polignac number, because 21230205 - 2¹ = 21230203 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230203) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3111 + ... + 7220.

It is an arithmetic number, because the mean of its divisors is an integer number (2138724).

Almost surely, 2^21230205 is an apocalyptic number.

It is an amenable number.

21230205 is a deficient number, since it is larger than the sum of its proper divisors (12989379).

21230205 is a wasteful number, since it uses less digits than its factorization.

21230205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10476.

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 21230205 is about 4607.6246591926. The cubic root of 21230205 is about 276.8968802083.

Adding to 21230205 its reverse (50203212), we get a palindrome (71433417).

The spelling of 21230205 in words is "twenty-one million, two hundred thirty thousand, two hundred five".