21323423 has 16 divisors (see below), whose sum is σ = 24896160. Its totient is φ = 18048000.

The previous prime is 21323417. The next prime is 21323441. The reversal of 21323423 is 32432312.

It is a cyclic number.

It is not a de Polignac number, because 21323423 - 2⁸ = 21323167 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21323395 and 21323404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323473) 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, 18323 + ... + 19451.

It is an arithmetic number, because the mean of its divisors is an integer number (1556010).

Almost surely, 2^21323423 is an apocalyptic number.

21323423 is a deficient number, since it is larger than the sum of its proper divisors (3572737).

21323423 is a wasteful number, since it uses less digits than its factorization.

21323423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1258.

The product of its digits is 864, while the sum is 20.

The square root of 21323423 is about 4617.7292038403. The cubic root of 21323423 is about 277.3015565799.

Adding to 21323423 its reverse (32432312), we get a palindrome (53755735).

Subtracting 21323423 from its reverse (32432312), we obtain a square (11108889 = 3333²).

It can be divided in two parts, 2132 and 3423, that added together give a palindrome (5555).

The spelling of 21323423 in words is "twenty-one million, three hundred twenty-three thousand, four hundred twenty-three".