221001112200821 has 2 divisors, whose sum is σ = 221001112200822. Its totient is φ = 221001112200820.

The previous prime is 221001112200719. The next prime is 221001112200857. The reversal of 221001112200821 is 128002211100122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188466522912721 + 32534589288100 = 13728311^2 + 5703910^2 .

It is a cyclic number.

It is not a de Polignac number, because 221001112200821 - 2³⁴ = 220983932331637 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221001112203821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110500556100410 + 110500556100411.

It is an arithmetic number, because the mean of its divisors is an integer number (110500556100411).

Almost surely, 2^{221001112200821} is an apocalyptic number.

It is an amenable number.

221001112200821 is a deficient number, since it is larger than the sum of its proper divisors (1).

221001112200821 is an equidigital number, since it uses as much as digits as its factorization.

221001112200821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 23.

Adding to 221001112200821 its reverse (128002211100122), we get a palindrome (349003323300943).

The spelling of 221001112200821 in words is "two hundred twenty-one trillion, one billion, one hundred twelve million, two hundred thousand, eight hundred twenty-one".