21432223 has 4 divisors (see below), whose sum is σ = 22692960. Its totient is φ = 20171488.

The previous prime is 21432211. The next prime is 21432233. The reversal of 21432223 is 32223412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21432223 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21432223.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432233) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 630343 + ... + 630376.

It is an arithmetic number, because the mean of its divisors is an integer number (5673240).

Almost surely, 2^21432223 is an apocalyptic number.

21432223 is a deficient number, since it is larger than the sum of its proper divisors (1260737).

21432223 is a wasteful number, since it uses less digits than its factorization.

21432223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260736.

The product of its digits is 576, while the sum is 19.

The square root of 21432223 is about 4629.4948968543. The cubic root of 21432223 is about 277.7723884406.

Adding to 21432223 its reverse (32223412), we get a palindrome (53655635).

The spelling of 21432223 in words is "twenty-one million, four hundred thirty-two thousand, two hundred twenty-three".