21242272 has 12 divisors (see below), whose sum is σ = 41820786. Its totient is φ = 10621120.

The previous prime is 21242237. The next prime is 21242339. The reversal of 21242272 is 27224212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 11532816 + 9709456 = 3396^2 + 3116^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331879 + ... + 331942.

Almost surely, 2^21242272 is an apocalyptic number.

It is an amenable number.

21242272 is a deficient number, since it is larger than the sum of its proper divisors (20578514).

21242272 is an equidigital number, since it uses as much as digits as its factorization.

21242272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663831 (or 663823 counting only the distinct ones).

The product of its digits is 896, while the sum is 22.

The square root of 21242272 is about 4608.9339331346. The cubic root of 21242272 is about 276.9493319203.

Adding to 21242272 its reverse (27224212), we get a palindrome (48466484).

The spelling of 21242272 in words is "twenty-one million, two hundred forty-two thousand, two hundred seventy-two".