21344123 has 4 divisors (see below), whose sum is σ = 21662760. Its totient is φ = 21025488.

The previous prime is 21344119. The next prime is 21344131. The reversal of 21344123 is 32144312.

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 21344123 - 2² = 21344119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21344095 and 21344104.

It is not an unprimeable number, because it can be changed into a prime (21344173) 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, 159218 + ... + 159351.

It is an arithmetic number, because the mean of its divisors is an integer number (5415690).

Almost surely, 2^21344123 is an apocalyptic number.

21344123 is a deficient number, since it is larger than the sum of its proper divisors (318637).

21344123 is an equidigital number, since it uses as much as digits as its factorization.

21344123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318636.

The product of its digits is 576, while the sum is 20.

The square root of 21344123 is about 4619.9700215478. The cubic root of 21344123 is about 277.3912589662.

Adding to 21344123 its reverse (32144312), we get a palindrome (53488435).

The spelling of 21344123 in words is "twenty-one million, three hundred forty-four thousand, one hundred twenty-three".