21000011100221 has 4 divisors (see below), whose sum is σ = 21000660744672. Its totient is φ = 20999361455772.

The previous prime is 21000011100203. The next prime is 21000011100361. The reversal of 21000011100221 is 12200111000012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21000011100221 - 2¹⁴ = 21000011083837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000011100521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 324773735 + ... + 324838388.

It is an arithmetic number, because the mean of its divisors is an integer number (5250165186168).

Almost surely, 2^{21000011100221} is an apocalyptic number.

It is an amenable number.

21000011100221 is a deficient number, since it is larger than the sum of its proper divisors (649644451).

21000011100221 is an equidigital number, since it uses as much as digits as its factorization.

21000011100221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 649644450.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21000011100221 its reverse (12200111000012), we get a palindrome (33200122100233).

The spelling of 21000011100221 in words is "twenty-one trillion, eleven million, one hundred thousand, two hundred twenty-one".