21205132 has 12 divisors (see below), whose sum is σ = 39963616. Its totient is φ = 9786960.

The previous prime is 21205127. The next prime is 21205139. The reversal of 21205132 is 23150212.

It is not an unprimeable number, because it can be changed into a prime (21205139) 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, 203844 + ... + 203947.

Almost surely, 2^21205132 is an apocalyptic number.

It is an amenable number.

21205132 is a deficient number, since it is larger than the sum of its proper divisors (18758484).

21205132 is a wasteful number, since it uses less digits than its factorization.

21205132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407808 (or 407806 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21205132 is about 4604.9030391529. The cubic root of 21205132 is about 276.7878316401.

Adding to 21205132 its reverse (23150212), we get a palindrome (44355344).

The spelling of 21205132 in words is "twenty-one million, two hundred five thousand, one hundred thirty-two".