21211212220201 has 4 divisors (see below), whose sum is σ = 21211988163412. Its totient is φ = 21210436276992.

The previous prime is 21211212220183. The next prime is 21211212220213. The reversal of 21211212220201 is 10202221211212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9279023730201 + 11932188490000 = 3046149^2 + 3454300^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211212220201 - 2⁹ = 21211212219689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21211212220291) 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, 387930600 + ... + 387985273.

It is an arithmetic number, because the mean of its divisors is an integer number (5302997040853).

Almost surely, 2^{21211212220201} is an apocalyptic number.

It is an amenable number.

21211212220201 is a deficient number, since it is larger than the sum of its proper divisors (775943211).

21211212220201 is an equidigital number, since it uses as much as digits as its factorization.

21211212220201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775943210.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21211212220201 its reverse (10202221211212), we get a palindrome (31413433431413).

The spelling of 21211212220201 in words is "twenty-one trillion, two hundred eleven billion, two hundred twelve million, two hundred twenty thousand, two hundred one".