20044021 has 4 divisors (see below), whose sum is σ = 20056032. Its totient is φ = 20032012.

The previous prime is 20044009. The next prime is 20044027. The reversal of 20044021 is 12044002.

20044021 = T₃₆₅₄ + T₃₆₅₅ + T₃₆₅₆.

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 a de Polignac number, because none of the positive numbers 2^k-20044021 is a prime.

It is a Smith number, since the sum of its digits (13) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20043992 and 20044010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20044027) 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, 3001 + ... + 7006.

It is an arithmetic number, because the mean of its divisors is an integer number (5014008).

Almost surely, 2^20044021 is an apocalyptic number.

20044021 is the 3656-th centered triangular number.

It is an amenable number.

20044021 is a deficient number, since it is larger than the sum of its proper divisors (12011).

20044021 is a wasteful number, since it uses less digits than its factorization.

20044021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12010.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 20044021 is about 4477.0549471723. The cubic root of 20044021 is about 271.6407680197.

Adding to 20044021 its reverse (12044002), we get a palindrome (32088023).

The spelling of 20044021 in words is "twenty million, forty-four thousand, twenty-one".