21242204 has 6 divisors (see below), whose sum is σ = 37173864. Its totient is φ = 10621100.

The previous prime is 21242203. The next prime is 21242237. The reversal of 21242204 is 40224212.

21242204 = 1626² + 1627² + ... + 1633².

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2655272 + ... + 2655279.

It is an arithmetic number, because the mean of its divisors is an integer number (6195644).

Almost surely, 2^21242204 is an apocalyptic number.

It is an amenable number.

21242204 is a deficient number, since it is larger than the sum of its proper divisors (15931660).

21242204 is a wasteful number, since it uses less digits than its factorization.

21242204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5310555 (or 5310553 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21242204 is about 4608.9265561517. The cubic root of 21242204 is about 276.9490363999.

Adding to 21242204 its reverse (40224212), we get a palindrome (61466416).

The spelling of 21242204 in words is "twenty-one million, two hundred forty-two thousand, two hundred four".