20000221 has 2 divisors, whose sum is σ = 20000222. Its totient is φ = 20000220.

The previous prime is 20000213. The next prime is 20000243. The reversal of 20000221 is 12200002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19980900 + 19321 = 4470^2 + 139^2 .

It is a cyclic number.

It is not a de Polignac number, because 20000221 - 2³ = 20000213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20000621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000110 + 10000111.

It is an arithmetic number, because the mean of its divisors is an integer number (10000111).

Almost surely, 2^20000221 is an apocalyptic number.

It is an amenable number.

20000221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20000221 is an equidigital number, since it uses as much as digits as its factorization.

20000221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 7.

The square root of 20000221 is about 4472.1606634825. The cubic root of 20000221 is about 271.4427614663.

Adding to 20000221 its reverse (12200002), we get a palindrome (32200223).

The spelling of 20000221 in words is "twenty million, two hundred twenty-one", and thus it is an aban number.