21543272 has 32 divisors (see below), whose sum is σ = 42439680. Its totient is φ = 10232640.

The previous prime is 21543271. The next prime is 21543289. The reversal of 21543272 is 27234512.

It is a super-2 number, since 2×21543272² = 928225136931968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21543271) 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 in 7 ways as a sum of consecutive naturals, for example, 34838 + ... + 35450.

It is an arithmetic number, because the mean of its divisors is an integer number (1326240).

Almost surely, 2^21543272 is an apocalyptic number.

It is an amenable number.

21543272 is a deficient number, since it is larger than the sum of its proper divisors (20896408).

21543272 is a wasteful number, since it uses less digits than its factorization.

21543272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 833 (or 829 counting only the distinct ones).

The product of its digits is 3360, while the sum is 26.

The square root of 21543272 is about 4641.4730420417. The cubic root of 21543272 is about 278.2513125199.

Adding to 21543272 its reverse (27234512), we get a palindrome (48777784).

The spelling of 21543272 in words is "twenty-one million, five hundred forty-three thousand, two hundred seventy-two".