21221221112001 has 6 divisors (see below), whose sum is σ = 30652874939570. Its totient is φ = 14147480741328.

The previous prime is 21221221111999. The next prime is 21221221112041. The reversal of 21221221112001 is 10021112212212.

21221221112001 is a `hidden beast` number, since 21 + 221 + 221 + 1 + 1 + 200 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21100940467776 + 120280644225 = 4593576^2 + 346815^2 .

It is not a de Polignac number, because 21221221112001 - 2¹ = 21221221111999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221221112041) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1178956728436 + ... + 1178956728453.

Almost surely, 2^{21221221112001} is an apocalyptic number.

It is an amenable number.

21221221112001 is a deficient number, since it is larger than the sum of its proper divisors (9431653827569).

21221221112001 is a wasteful number, since it uses less digits than its factorization.

21221221112001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2357913456895 (or 2357913456892 counting only the distinct ones).

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

Adding to 21221221112001 its reverse (10021112212212), we get a palindrome (31242333324213).

The spelling of 21221221112001 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty-one million, one hundred twelve thousand, one".