21236023 has 16 divisors (see below), whose sum is σ = 22809600. Its totient is φ = 19736640.

The previous prime is 21236021. The next prime is 21236041. The reversal of 21236023 is 32063212.

It is not a de Polignac number, because 21236023 - 2¹ = 21236021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236021) 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, 118548 + ... + 118726.

It is an arithmetic number, because the mean of its divisors is an integer number (1425600).

Almost surely, 2^21236023 is an apocalyptic number.

21236023 is a deficient number, since it is larger than the sum of its proper divisors (1573577).

21236023 is a wasteful number, since it uses less digits than its factorization.

21236023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342.

The product of its (nonzero) digits is 432, while the sum is 19.

The square root of 21236023 is about 4608.2559607730. The cubic root of 21236023 is about 276.9221718295.

Adding to 21236023 its reverse (32063212), we get a palindrome (53299235).

The spelling of 21236023 in words is "twenty-one million, two hundred thirty-six thousand, twenty-three".