21540332 has 12 divisors (see below), whose sum is σ = 41122536. Its totient is φ = 9791040.

The previous prime is 21540317. The next prime is 21540341. The reversal of 21540332 is 23304512.

It is a happy number.

It is an unprimeable number.

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, 244733 + ... + 244820.

It is an arithmetic number, because the mean of its divisors is an integer number (3426878).

Almost surely, 2^21540332 is an apocalyptic number.

21540332 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21540332 is a deficient number, since it is larger than the sum of its proper divisors (19582204).

21540332 is a wasteful number, since it uses less digits than its factorization.

21540332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489568 (or 489566 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 21540332 is about 4641.1563214354. The cubic root of 21540332 is about 278.2386543364.

Adding to 21540332 its reverse (23304512), we get a palindrome (44844844).

The spelling of 21540332 in words is "twenty-one million, five hundred forty thousand, three hundred thirty-two".