20644321 has 4 divisors (see below), whose sum is σ = 20656944. Its totient is φ = 20631700.

The previous prime is 20644319. The next prime is 20644331. The reversal of 20644321 is 12344602.

It is a happy number.

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 20644321 - 2¹ = 20644319 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20644292 and 20644301.

It is not an unprimeable number, because it can be changed into a prime (20644331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3415 + ... + 7276.

It is an arithmetic number, because the mean of its divisors is an integer number (5164236).

Almost surely, 2^20644321 is an apocalyptic number.

It is an amenable number.

20644321 is a deficient number, since it is larger than the sum of its proper divisors (12623).

20644321 is a wasteful number, since it uses less digits than its factorization.

20644321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12622.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 20644321 is about 4543.6022052992. The cubic root of 20644321 is about 274.3259347925.

Adding to 20644321 its reverse (12344602), we get a palindrome (32988923).

The spelling of 20644321 in words is "twenty million, six hundred forty-four thousand, three hundred twenty-one".