21232205 has 16 divisors (see below), whose sum is σ = 26535600. Its totient is φ = 16289280.

The previous prime is 21232199. The next prime is 21232207. The reversal of 21232205 is 50223212.

It can be written as a sum of positive squares in 8 ways, for example, as 702244 + 20529961 = 838^2 + 4531^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21232205 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21232207) 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, 25841 + ... + 26649.

It is an arithmetic number, because the mean of its divisors is an integer number (1658475).

Almost surely, 2^21232205 is an apocalyptic number.

It is an amenable number.

21232205 is a deficient number, since it is larger than the sum of its proper divisors (5303395).

21232205 is a wasteful number, since it uses less digits than its factorization.

21232205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1024.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21232205 is about 4607.8416856485. The cubic root of 21232205 is about 276.9055749959.

Adding to 21232205 its reverse (50223212), we get a palindrome (71455417).

The spelling of 21232205 in words is "twenty-one million, two hundred thirty-two thousand, two hundred five".