21124023 has 4 divisors (see below), whose sum is σ = 28165368. Its totient is φ = 14082680.

The previous prime is 21124021. The next prime is 21124031. The reversal of 21124023 is 32042112.

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 21124023 - 2¹ = 21124021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21123993 and 21124011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124021) 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, 3520668 + ... + 3520673.

It is an arithmetic number, because the mean of its divisors is an integer number (7041342).

Almost surely, 2^21124023 is an apocalyptic number.

21124023 is a deficient number, since it is larger than the sum of its proper divisors (7041345).

21124023 is an equidigital number, since it uses as much as digits as its factorization.

21124023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7041344.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21124023 is about 4596.0877928952. The cubic root of 21124023 is about 276.4344789906.

Adding to 21124023 its reverse (32042112), we get a palindrome (53166135).

The spelling of 21124023 in words is "twenty-one million, one hundred twenty-four thousand, twenty-three".