21344443 has 4 divisors (see below), whose sum is σ = 21362128. Its totient is φ = 21326760.

The previous prime is 21344419. The next prime is 21344447. The reversal of 21344443 is 34444312.

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

It is a cyclic number.

It is not a de Polignac number, because 21344443 - 2¹³ = 21336251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21344447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6888 + ... + 9493.

It is an arithmetic number, because the mean of its divisors is an integer number (5340532).

Almost surely, 2^21344443 is an apocalyptic number.

21344443 is a deficient number, since it is larger than the sum of its proper divisors (17685).

21344443 is a wasteful number, since it uses less digits than its factorization.

21344443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17684.

The product of its digits is 4608, while the sum is 25.

The square root of 21344443 is about 4620.0046536773. The cubic root of 21344443 is about 277.3926452144.

Adding to 21344443 its reverse (34444312), we get a palindrome (55788755).

The spelling of 21344443 in words is "twenty-one million, three hundred forty-four thousand, four hundred forty-three".