21044423 has 2 divisors, whose sum is σ = 21044424. Its totient is φ = 21044422.

The previous prime is 21044407. The next prime is 21044431. The reversal of 21044423 is 32444012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21044423 - 2⁴ = 21044407 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21044395 and 21044404.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21044473) 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 as a sum of consecutive naturals, namely, 10522211 + 10522212.

It is an arithmetic number, because the mean of its divisors is an integer number (10522212).

Almost surely, 2^21044423 is an apocalyptic number.

21044423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21044423 is an equidigital number, since it uses as much as digits as its factorization.

21044423 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 21044423 is about 4587.4200810477. The cubic root of 21044423 is about 276.0868198127.

Adding to 21044423 its reverse (32444012), we get a palindrome (53488435).

The spelling of 21044423 in words is "twenty-one million, forty-four thousand, four hundred twenty-three".