21226636 has 6 divisors (see below), whose sum is σ = 37146620. Its totient is φ = 10613316.

The previous prime is 21226633. The next prime is 21226663. The reversal of 21226636 is 63662212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21226633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2653326 + ... + 2653333.

Almost surely, 2^21226636 is an apocalyptic number.

It is an amenable number.

21226636 is a deficient number, since it is larger than the sum of its proper divisors (15919984).

21226636 is a wasteful number, since it uses less digits than its factorization.

21226636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5306663 (or 5306661 counting only the distinct ones).

The product of its digits is 5184, while the sum is 28.

The square root of 21226636 is about 4607.2373500830. The cubic root of 21226636 is about 276.8813630030.

Adding to 21226636 its reverse (63662212), we get a palindrome (84888848).

The spelling of 21226636 in words is "twenty-one million, two hundred twenty-six thousand, six hundred thirty-six".