21424123 has 10 divisors (see below), whose sum is σ = 24996124. Its totient is φ = 18361476.

The previous prime is 21424093. The next prime is 21424129. The reversal of 21424123 is 32142412.

It is not a de Polignac number, because 21424123 - 2¹³ = 21415931 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21424123.

It is not an unprimeable number, because it can be changed into a prime (21424129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2061 + ... + 6862.

Almost surely, 2^21424123 is an apocalyptic number.

21424123 is a deficient number, since it is larger than the sum of its proper divisors (3572001).

21424123 is an frugal number, since it uses more digits than its factorization.

21424123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8951 (or 8930 counting only the distinct ones).

The product of its digits is 384, while the sum is 19.

The square root of 21424123 is about 4628.6199887223. The cubic root of 21424123 is about 277.7373906734.

Adding to 21424123 its reverse (32142412), we get a palindrome (53566535).

The spelling of 21424123 in words is "twenty-one million, four hundred twenty-four thousand, one hundred twenty-three".