21023023 has 6 divisors (see below), whose sum is σ = 24040184. Its totient is φ = 18009336.

The previous prime is 21023017. The next prime is 21023047. The reversal of 21023023 is 32032012.

It is a happy number.

It is not a de Polignac number, because 21023023 - 2²¹ = 18925871 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21022994 and 21023012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11265 + ... + 12997.

Almost surely, 2^21023023 is an apocalyptic number.

21023023 is a deficient number, since it is larger than the sum of its proper divisors (3017161).

21023023 is an frugal number, since it uses more digits than its factorization.

21023023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3473 (or 1740 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21023023 is about 4585.0870220749. The cubic root of 21023023 is about 275.9932041665.

Adding to 21023023 its reverse (32032012), we get a palindrome (53055035).

The spelling of 21023023 in words is "twenty-one million, twenty-three thousand, twenty-three".