21201200221 has 2 divisors, whose sum is σ = 21201200222. Its totient is φ = 21201200220.

The previous prime is 21201200177. The next prime is 21201200227. The reversal of 21201200221 is 12200210212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21035151225 + 166048996 = 145035^2 + 12886^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201200221 - 2⁷ = 21201200093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201200227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600600110 + 10600600111.

It is an arithmetic number, because the mean of its divisors is an integer number (10600600111).

Almost surely, 2^21201200221 is an apocalyptic number.

It is an amenable number.

21201200221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201200221 is an equidigital number, since it uses as much as digits as its factorization.

21201200221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21201200221 its reverse (12200210212), we get a palindrome (33401410433).

Subtracting from 21201200221 its reverse (12200210212), we obtain a palindrome (9000990009).

The spelling of 21201200221 in words is "twenty-one billion, two hundred one million, two hundred thousand, two hundred twenty-one".