21023273 has 4 divisors (see below), whose sum is σ = 21183888. Its totient is φ = 20862660.

The previous prime is 21023269. The next prime is 21023279. The reversal of 21023273 is 37232012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21023273 - 2² = 21023269 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21023279) 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, 80111 + ... + 80372.

It is an arithmetic number, because the mean of its divisors is an integer number (5295972).

Almost surely, 2^21023273 is an apocalyptic number.

It is an amenable number.

21023273 is a deficient number, since it is larger than the sum of its proper divisors (160615).

21023273 is a wasteful number, since it uses less digits than its factorization.

21023273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160614.

The product of its (nonzero) digits is 504, while the sum is 20.

The square root of 21023273 is about 4585.1142842900. The cubic root of 21023273 is about 275.9942981739.

Adding to 21023273 its reverse (37232012), we get a palindrome (58255285).

The spelling of 21023273 in words is "twenty-one million, twenty-three thousand, two hundred seventy-three".