21221121100221 has 12 divisors (see below), whose sum is σ = 35031691975072. Its totient is φ = 12126354914376.

The previous prime is 21221121100141. The next prime is 21221121100229. The reversal of 21221121100221 is 12200112112212.

21221121100221 is a `hidden beast` number, since 2 + 1 + 221 + 121 + 100 + 221 = 666.

It is not a de Polignac number, because 21221121100221 - 2¹⁰ = 21221121099197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221121100194 and 21221121100203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221121100229) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 168421595971 + ... + 168421596096.

Almost surely, 2^{21221121100221} is an apocalyptic number.

21221121100221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21221121100221 is a deficient number, since it is larger than the sum of its proper divisors (13810570874851).

21221121100221 is a wasteful number, since it uses less digits than its factorization.

21221121100221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336843192080 (or 336843192077 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21221121100221 its reverse (12200112112212), we get a palindrome (33421233212433).

The spelling of 21221121100221 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twenty-one million, one hundred thousand, two hundred twenty-one".