21201211211121 has 6 divisors (see below), whose sum is σ = 30623971749410. Its totient is φ = 14134140807408.

The previous prime is 21201211211119. The next prime is 21201211211123. The reversal of 21201211211121 is 12111211210212.

It is a happy number.

21201211211121 is a `hidden beast` number, since 2 + 120 + 1 + 211 + 211 + 121 = 666.

It is an interprime number because it is at equal distance from previous prime (21201211211119) and next prime (21201211211123).

It can be written as a sum of positive squares in only one way, i.e., 16236781601121 + 4964429610000 = 4029489^2 + 2228100^2 .

It is not a de Polignac number, because 21201211211121 - 2¹ = 21201211211119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201211211094 and 21201211211103.

It is not an unprimeable number, because it can be changed into a prime (21201211211123) 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, 1177845067276 + ... + 1177845067293.

Almost surely, 2^{21201211211121} is an apocalyptic number.

It is an amenable number.

21201211211121 is a deficient number, since it is larger than the sum of its proper divisors (9422760538289).

21201211211121 is a wasteful number, since it uses less digits than its factorization.

21201211211121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2355690134575 (or 2355690134572 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21201211211121 its reverse (12111211210212), we get a palindrome (33312422421333).

Subtracting from 21201211211121 its reverse (12111211210212), we obtain a palindrome (9090000000909).

The spelling of 21201211211121 in words is "twenty-one trillion, two hundred one billion, two hundred eleven million, two hundred eleven thousand, one hundred twenty-one".