21212212112101 has 2 divisors, whose sum is σ = 21212212112102. Its totient is φ = 21212212112100.

The previous prime is 21212212112099. The next prime is 21212212112137. The reversal of 21212212112101 is 10121121221212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12149860492225 + 9062351619876 = 3485665^2 + 3010374^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212212112101 - 2¹ = 21212212112099 is a prime.

Together with 21212212112099, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212212112141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606106056050 + 10606106056051.

It is an arithmetic number, because the mean of its divisors is an integer number (10606106056051).

Almost surely, 2^{21212212112101} is an apocalyptic number.

It is an amenable number.

21212212112101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212212112101 is an equidigital number, since it uses as much as digits as its factorization.

21212212112101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21212212112101 its reverse (10121121221212), we get a palindrome (31333333333313).

The spelling of 21212212112101 in words is "twenty-one trillion, two hundred twelve billion, two hundred twelve million, one hundred twelve thousand, one hundred one".