20023021 has 4 divisors (see below), whose sum is σ = 20713500. Its totient is φ = 19332544.

The previous prime is 20023009. The next prime is 20023027. The reversal of 20023021 is 12032002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8934121 + 11088900 = 2989^2 + 3330^2 .

It is a cyclic number.

It is not a de Polignac number, because 20023021 - 2¹⁵ = 19990253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20022989 and 20023007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20023027) 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, 345196 + ... + 345253.

It is an arithmetic number, because the mean of its divisors is an integer number (5178375).

Almost surely, 2^20023021 is an apocalyptic number.

It is an amenable number.

20023021 is a deficient number, since it is larger than the sum of its proper divisors (690479).

20023021 is an equidigital number, since it uses as much as digits as its factorization.

20023021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 690478.

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

The square root of 20023021 is about 4474.7090408204. The cubic root of 20023021 is about 271.5458694052.

Adding to 20023021 its reverse (12032002), we get a palindrome (32055023).

The spelling of 20023021 in words is "twenty million, twenty-three thousand, twenty-one".