21232636 has 24 divisors (see below), whose sum is σ = 38060064. Its totient is φ = 10361280.

The previous prime is 21232571. The next prime is 21232639. The reversal of 21232636 is 63623212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21232636.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21232639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41961 + ... + 42463.

It is an arithmetic number, because the mean of its divisors is an integer number (1585836).

Almost surely, 2^21232636 is an apocalyptic number.

It is an amenable number.

21232636 is a deficient number, since it is larger than the sum of its proper divisors (16827428).

21232636 is a wasteful number, since it uses less digits than its factorization.

21232636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 741 (or 739 counting only the distinct ones).

The product of its digits is 2592, while the sum is 25.

The square root of 21232636 is about 4607.8884535110. Note that the first 3 decimals coincide. The cubic root of 21232636 is about 276.9074486511.

Adding to 21232636 its reverse (63623212), we get a palindrome (84855848).

The spelling of 21232636 in words is "twenty-one million, two hundred thirty-two thousand, six hundred thirty-six".