21363633 has 12 divisors (see below), whose sum is σ = 31923060. Its totient is φ = 13751136.

The previous prime is 21363613. The next prime is 21363637. The reversal of 21363633 is 33636312.

21363633 is a `hidden beast` number, since 21 + 3 + 6 + 3 + 633 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15944049 + 5419584 = 3993^2 + 2328^2 .

It is not a de Polignac number, because 21363633 - 2¹⁰ = 21362609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21363597 and 21363606.

It is not an unprimeable number, because it can be changed into a prime (21363637) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40666 + ... + 41187.

It is an arithmetic number, because the mean of its divisors is an integer number (2660255).

Almost surely, 2^21363633 is an apocalyptic number.

It is an amenable number.

21363633 is a deficient number, since it is larger than the sum of its proper divisors (10559427).

21363633 is a wasteful number, since it uses less digits than its factorization.

21363633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81888 (or 81885 counting only the distinct ones).

The product of its digits is 5832, while the sum is 27.

The square root of 21363633 is about 4622.0810248199. The cubic root of 21363633 is about 277.4757514726.

Adding to 21363633 its reverse (33636312), we get a palindrome (54999945).

The spelling of 21363633 in words is "twenty-one million, three hundred sixty-three thousand, six hundred thirty-three".