20423221 has 32 divisors (see below), whose sum is σ = 26611200. Its totient is φ = 15240960.

The previous prime is 20423213. The next prime is 20423231. The reversal of 20423221 is 12232402.

It is not a de Polignac number, because 20423221 - 2³ = 20423213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20423195 and 20423204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20423201) 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 31 ways as a sum of consecutive naturals, for example, 187315 + ... + 187423.

It is an arithmetic number, because the mean of its divisors is an integer number (831600).

Almost surely, 2^20423221 is an apocalyptic number.

It is an amenable number.

20423221 is a deficient number, since it is larger than the sum of its proper divisors (6187979).

20423221 is a wasteful number, since it uses less digits than its factorization.

20423221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 20423221 is about 4519.2057930570. The cubic root of 20423221 is about 273.3430770206.

Adding to 20423221 its reverse (12232402), we get a palindrome (32655623).

The spelling of 20423221 in words is "twenty million, four hundred twenty-three thousand, two hundred twenty-one".