21244423 has 4 divisors (see below), whose sum is σ = 21696480. Its totient is φ = 20792368.

The previous prime is 21244417. The next prime is 21244459. The reversal of 21244423 is 32444212.

It is a happy number.

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-21244423 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21244394 and 21244403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244463) 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, 225958 + ... + 226051.

It is an arithmetic number, because the mean of its divisors is an integer number (5424120).

Almost surely, 2^21244423 is an apocalyptic number.

21244423 is a deficient number, since it is larger than the sum of its proper divisors (452057).

21244423 is an equidigital number, since it uses as much as digits as its factorization.

21244423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452056.

The product of its digits is 1536, while the sum is 22.

The square root of 21244423 is about 4609.1672783704. The cubic root of 21244423 is about 276.9586796007.

Adding to 21244423 its reverse (32444212), we get a palindrome (53688635).

The spelling of 21244423 in words is "twenty-one million, two hundred forty-four thousand, four hundred twenty-three".