21211221210101 has 4 divisors (see below), whose sum is σ = 22842853610892. Its totient is φ = 19579588809312.

The previous prime is 21211221210031. The next prime is 21211221210169. The reversal of 21211221210101 is 10101212211212.

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 4910097583876 + 16301123626225 = 2215874^2 + 4037465^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211221210101 - 2²² = 21211217015797 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21211221210101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211221210181) 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, 815816200376 + ... + 815816200401.

It is an arithmetic number, because the mean of its divisors is an integer number (5710713402723).

Almost surely, 2^{21211221210101} is an apocalyptic number.

It is an amenable number.

21211221210101 is a deficient number, since it is larger than the sum of its proper divisors (1631632400791).

21211221210101 is a wasteful number, since it uses less digits than its factorization.

21211221210101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1631632400790.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21211221210101 its reverse (10101212211212), we get a palindrome (31312433421313).

The spelling of 21211221210101 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred ten thousand, one hundred one".