21422123 has 4 divisors (see below), whose sum is σ = 21826368. Its totient is φ = 21017880.

The previous prime is 21422119. The next prime is 21422129. The reversal of 21422123 is 32122412.

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 21422123 - 2² = 21422119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21422129) 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 in 3 ways as a sum of consecutive naturals, for example, 202043 + ... + 202148.

It is an arithmetic number, because the mean of its divisors is an integer number (5456592).

Almost surely, 2^21422123 is an apocalyptic number.

21422123 is a deficient number, since it is larger than the sum of its proper divisors (404245).

21422123 is an equidigital number, since it uses as much as digits as its factorization.

21422123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404244.

The product of its digits is 192, while the sum is 17.

The square root of 21422123 is about 4628.4039365639. The cubic root of 21422123 is about 277.7287478915.

Adding to 21422123 its reverse (32122412), we get a palindrome (53544535).

The spelling of 21422123 in words is "twenty-one million, four hundred twenty-two thousand, one hundred twenty-three".