21323023 has 4 divisors (see below), whose sum is σ = 21344400. Its totient is φ = 21301648.

The previous prime is 21323021. The next prime is 21323053. The reversal of 21323023 is 32032312.

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 21323023 - 2¹ = 21323021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21322988 and 21323006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323021) 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, 9115 + ... + 11212.

It is an arithmetic number, because the mean of its divisors is an integer number (5336100).

Almost surely, 2^21323023 is an apocalyptic number.

21323023 is a deficient number, since it is larger than the sum of its proper divisors (21377).

21323023 is a wasteful number, since it uses less digits than its factorization.

21323023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21376.

The product of its (nonzero) digits is 216, while the sum is 16.

The square root of 21323023 is about 4617.6858923058. The cubic root of 21323023 is about 277.2998226288.

Adding to 21323023 its reverse (32032312), we get a palindrome (53355335).

The spelling of 21323023 in words is "twenty-one million, three hundred twenty-three thousand, twenty-three".