21222524 has 24 divisors (see below), whose sum is σ = 37887696. Its totient is φ = 10400000.

The previous prime is 21222503. The next prime is 21222529. The reversal of 21222524 is 42522212.

It is a junction number, because it is equal to n+sod(n) for n = 21222496 and 21222505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222529) 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 7 ways as a sum of consecutive naturals, for example, 52724 + ... + 53124.

It is an arithmetic number, because the mean of its divisors is an integer number (1578654).

Almost surely, 2^21222524 is an apocalyptic number.

It is an amenable number.

21222524 is a deficient number, since it is larger than the sum of its proper divisors (16665172).

21222524 is a wasteful number, since it uses less digits than its factorization.

21222524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637 (or 635 counting only the distinct ones).

The product of its digits is 640, while the sum is 20.

The square root of 21222524 is about 4606.7910740558. The cubic root of 21222524 is about 276.8634827998.

Adding to 21222524 its reverse (42522212), we get a palindrome (63744736).

The spelling of 21222524 in words is "twenty-one million, two hundred twenty-two thousand, five hundred twenty-four".