21221020201 has 2 divisors, whose sum is σ = 21221020202. Its totient is φ = 21221020200.

The previous prime is 21221020199. The next prime is 21221020217. The reversal of 21221020201 is 10202012212.

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., 15851061801 + 5369958400 = 125901^2 + 73280^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221020201 - 2¹ = 21221020199 is a prime.

Together with 21221020199, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21221020241) 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 as a sum of consecutive naturals, namely, 10610510100 + 10610510101.

It is an arithmetic number, because the mean of its divisors is an integer number (10610510101).

Almost surely, 2^21221020201 is an apocalyptic number.

It is an amenable number.

21221020201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221020201 is an equidigital number, since it uses as much as digits as its factorization.

21221020201 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 21221020201 its reverse (10202012212), we get a palindrome (31423032413).

The spelling of 21221020201 in words is "twenty-one billion, two hundred twenty-one million, twenty thousand, two hundred one".