21624212 has 12 divisors (see below), whose sum is σ = 38556756. Its totient is φ = 10608000.

The previous prime is 21624203. The next prime is 21624263. The reversal of 21624212 is 21242612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 7214596 + 14409616 = 2686^2 + 3796^2 .

It is a congruent 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, 50789 + ... + 51212.

It is an arithmetic number, because the mean of its divisors is an integer number (3213063).

Almost surely, 2^21624212 is an apocalyptic number.

It is an amenable number.

21624212 is a deficient number, since it is larger than the sum of its proper divisors (16932544).

21624212 is a wasteful number, since it uses less digits than its factorization.

21624212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102058 (or 102056 counting only the distinct ones).

The product of its digits is 384, while the sum is 20.

The square root of 21624212 is about 4650.1840823778. The cubic root of 21624212 is about 278.5993487059.

Adding to 21624212 its reverse (21242612), we get a palindrome (42866824).

The spelling of 21624212 in words is "twenty-one million, six hundred twenty-four thousand, two hundred twelve".