21200023 has 4 divisors (see below), whose sum is σ = 22830808. Its totient is φ = 19569240.

The previous prime is 21200021. The next prime is 21200041. The reversal of 21200023 is 32000212.

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 21200023 - 2¹ = 21200021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21199982 and 21200009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 815373 + ... + 815398.

It is an arithmetic number, because the mean of its divisors is an integer number (5707702).

Almost surely, 2^21200023 is an apocalyptic number.

21200023 is a deficient number, since it is larger than the sum of its proper divisors (1630785).

21200023 is a wasteful number, since it uses less digits than its factorization.

21200023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1630784.

The product of its (nonzero) digits is 24, while the sum is 10.

The square root of 21200023 is about 4604.3482709283. The cubic root of 21200023 is about 276.7656008170.

Adding to 21200023 its reverse (32000212), we get a palindrome (53200235).

The spelling of 21200023 in words is "twenty-one million, two hundred thousand, twenty-three".