21012221200221 has 16 divisors (see below), whose sum is σ = 32767596414400. Its totient is φ = 13270876547184.

The previous prime is 21012221200177. The next prime is 21012221200231. The reversal of 21012221200221 is 12200212221012.

It is a happy number.

21012221200221 is a `hidden beast` number, since 2 + 10 + 12 + 221 + 200 + 221 = 666.

It is not a de Polignac number, because 21012221200221 - 2⁹ = 21012221199709 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21012221200194 and 21012221200203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012221200231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20479747246 + ... + 20479748271.

It is an arithmetic number, because the mean of its divisors is an integer number (2047974775900).

Almost surely, 2^{21012221200221} is an apocalyptic number.

It is an amenable number.

21012221200221 is a deficient number, since it is larger than the sum of its proper divisors (11755375214179).

21012221200221 is a wasteful number, since it uses less digits than its factorization.

21012221200221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40959495545 (or 40959495539 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21012221200221 its reverse (12200212221012), we get a palindrome (33212433421233).

The spelling of 21012221200221 in words is "twenty-one trillion, twelve billion, two hundred twenty-one million, two hundred thousand, two hundred twenty-one".