21423633 has 24 divisors (see below), whose sum is σ = 36252000. Its totient is φ = 11128320.

The previous prime is 21423631. The next prime is 21423641. The reversal of 21423633 is 33632412.

It is not a de Polignac number, because 21423633 - 2¹ = 21423631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423631) 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 23 ways as a sum of consecutive naturals, for example, 5008 + ... + 8241.

It is an arithmetic number, because the mean of its divisors is an integer number (1510500).

Almost surely, 2^21423633 is an apocalyptic number.

It is an amenable number.

21423633 is a deficient number, since it is larger than the sum of its proper divisors (14828367).

21423633 is a wasteful number, since it uses less digits than its factorization.

21423633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13277 (or 13270 counting only the distinct ones).

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

The square root of 21423633 is about 4628.5670568762. The cubic root of 21423633 is about 277.7352732416.

It can be divided in two parts, 2142 and 3633, that added together give a palindrome (5775).

The spelling of 21423633 in words is "twenty-one million, four hundred twenty-three thousand, six hundred thirty-three".