21201212212101 has 6 divisors (see below), whose sum is σ = 30623973195270. Its totient is φ = 14134141474728.

The previous prime is 21201212212097. The next prime is 21201212212109. The reversal of 21201212212101 is 10121221210212.

21201212212101 is a `hidden beast` number, since 21 + 201 + 212 + 21 + 210 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 18103101791076 + 3098110421025 = 4254774^2 + 1760145^2 .

It is not a de Polignac number, because 21201212212101 - 2² = 21201212212097 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201212212109) 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, 1177845122886 + ... + 1177845122903.

It is an arithmetic number, because the mean of its divisors is an integer number (5103995532545).

Almost surely, 2^{21201212212101} is an apocalyptic number.

It is an amenable number.

21201212212101 is a deficient number, since it is larger than the sum of its proper divisors (9422760983169).

21201212212101 is a wasteful number, since it uses less digits than its factorization.

21201212212101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2355690245795 (or 2355690245792 counting only the distinct ones).

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

Adding to 21201212212101 its reverse (10121221210212), we get a palindrome (31322433422313).

The spelling of 21201212212101 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, two hundred twelve thousand, one hundred one".