21221232 has 20 divisors (see below), whose sum is σ = 54821640. Its totient is φ = 7073728.

The previous prime is 21221171. The next prime is 21221237. The reversal of 21221232 is 23212212.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221007 + ... + 221102.

It is an arithmetic number, because the mean of its divisors is an integer number (2741082).

Almost surely, 2^21221232 is an apocalyptic number.

It is an amenable number.

21221232 is an abundant number, since it is smaller than the sum of its proper divisors (33600408).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221232 is a wasteful number, since it uses less digits than its factorization.

21221232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442120 (or 442114 counting only the distinct ones).

The product of its digits is 96, while the sum is 15.

The square root of 21221232 is about 4606.6508441600. The cubic root of 21221232 is about 276.8578643214.

Adding to 21221232 its reverse (23212212), we get a palindrome (44433444).

The spelling of 21221232 in words is "twenty-one million, two hundred twenty-one thousand, two hundred thirty-two".