21242216 has 16 divisors (see below), whose sum is σ = 40424640. Its totient is φ = 10462320.

The previous prime is 21242203. The next prime is 21242237. The reversal of 21242216 is 61224212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19280 + ... + 20351.

It is an arithmetic number, because the mean of its divisors is an integer number (2526540).

Almost surely, 2^21242216 is an apocalyptic number.

It is an amenable number.

21242216 is a deficient number, since it is larger than the sum of its proper divisors (19182424).

21242216 is a wasteful number, since it uses less digits than its factorization.

21242216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39704 (or 39700 counting only the distinct ones).

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

The square root of 21242216 is about 4608.9278579730. The cubic root of 21242216 is about 276.9490885506.

Adding to 21242216 its reverse (61224212), we get a palindrome (82466428).

The spelling of 21242216 in words is "twenty-one million, two hundred forty-two thousand, two hundred sixteen".