21243633 has 8 divisors (see below), whose sum is σ = 28605696. Its totient is φ = 14022000.

The previous prime is 21243611. The next prime is 21243637. The reversal of 21243633 is 33634212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21243633 - 2¹⁴ = 21227249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21243637) 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 in 7 ways as a sum of consecutive naturals, for example, 34753 + ... + 35358.

It is an arithmetic number, because the mean of its divisors is an integer number (3575712).

Almost surely, 2^21243633 is an apocalyptic number.

It is an amenable number.

21243633 is a deficient number, since it is larger than the sum of its proper divisors (7362063).

21243633 is a wasteful number, since it uses less digits than its factorization.

21243633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70215.

The product of its digits is 2592, while the sum is 24.

The square root of 21243633 is about 4609.0815787964. The cubic root of 21243633 is about 276.9552465417.

Adding to 21243633 its reverse (33634212), we get a palindrome (54877845).

The spelling of 21243633 in words is "twenty-one million, two hundred forty-three thousand, six hundred thirty-three".