21010212212111 has 4 divisors (see below), whose sum is σ = 21026336704752. Its totient is φ = 20994087719472.

The previous prime is 21010212212071. The next prime is 21010212212123. The reversal of 21010212212111 is 11121221201012.

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

It is a cyclic number.

It is not a de Polignac number, because 21010212212111 - 2⁶ = 21010212212047 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 21010212212111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010212212141) 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, 8062244366 + ... + 8062246971.

It is an arithmetic number, because the mean of its divisors is an integer number (5256584176188).

Almost surely, 2^{21010212212111} is an apocalyptic number.

21010212212111 is a deficient number, since it is larger than the sum of its proper divisors (16124492641).

21010212212111 is a wasteful number, since it uses less digits than its factorization.

21010212212111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16124492640.

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

Adding to 21010212212111 its reverse (11121221201012), we get a palindrome (32131433413123).

The spelling of 21010212212111 in words is "twenty-one trillion, ten billion, two hundred twelve million, two hundred twelve thousand, one hundred eleven".