21261232 has 10 divisors (see below), whose sum is σ = 41193668. Its totient is φ = 10630608.

The previous prime is 21261217. The next prime is 21261239. The reversal of 21261232 is 23216212.

It is not an unprimeable number, because it can be changed into a prime (21261239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 664398 + ... + 664429.

Almost surely, 2^21261232 is an apocalyptic number.

It is an amenable number.

21261232 is a deficient number, since it is larger than the sum of its proper divisors (19932436).

21261232 is a wasteful number, since it uses less digits than its factorization.

21261232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1328835 (or 1328829 counting only the distinct ones).

The product of its digits is 288, while the sum is 19.

The square root of 21261232 is about 4610.9903491549. The cubic root of 21261232 is about 277.0317053727.

Adding to 21261232 its reverse (23216212), we get a palindrome (44477444).

The spelling of 21261232 in words is "twenty-one million, two hundred sixty-one thousand, two hundred thirty-two".