21126423 has 16 divisors (see below), whose sum is σ = 29779200. Its totient is φ = 13285440.

The previous prime is 21126421. The next prime is 21126431. The reversal of 21126423 is 32462112.

It is not a de Polignac number, because 21126423 - 2¹ = 21126421 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21126423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15358 + ... + 16676.

It is an arithmetic number, because the mean of its divisors is an integer number (1861200).

Almost surely, 2^21126423 is an apocalyptic number.

21126423 is a deficient number, since it is larger than the sum of its proper divisors (8652777).

21126423 is a wasteful number, since it uses less digits than its factorization.

21126423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1622.

The product of its digits is 576, while the sum is 21.

The square root of 21126423 is about 4596.3488770980. The cubic root of 21126423 is about 276.4449476030. Note that the first 3 decimals are identical.

Adding to 21126423 its reverse (32462112), we get a palindrome (53588535).

The spelling of 21126423 in words is "twenty-one million, one hundred twenty-six thousand, four hundred twenty-three".