20020221 has 24 divisors (see below), whose sum is σ = 31395000. Its totient is φ = 12220416.

The previous prime is 20020207. The next prime is 20020223. The reversal of 20020221 is 12202002.

It can be written as a sum of positive squares in 4 ways, for example, as 756900 + 19263321 = 870^2 + 4389^2 .

It is not a de Polignac number, because 20020221 - 2⁶ = 20020157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20020223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15405 + ... + 16653.

It is an arithmetic number, because the mean of its divisors is an integer number (1308125).

Almost surely, 2^20020221 is an apocalyptic number.

It is an amenable number.

20020221 is a deficient number, since it is larger than the sum of its proper divisors (11374779).

20020221 is a wasteful number, since it uses less digits than its factorization.

20020221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1405 (or 1402 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 20020221 is about 4474.3961603774. The cubic root of 20020221 is about 271.5332112441.

Adding to 20020221 its reverse (12202002), we get a palindrome (32222223).

The spelling of 20020221 in words is "twenty million, twenty thousand, two hundred twenty-one".