21216111231011 has 4 divisors (see below), whose sum is σ = 21422092893552. Its totient is φ = 21010129568472.

The previous prime is 21216111230989. The next prime is 21216111231037. The reversal of 21216111231011 is 11013211161212.

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 21216111231011 - 2³⁰ = 21215037489187 is a prime.

It is a super-3 number, since 3×21216111231011³ (a number of 41 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21216111230011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102990831116 + ... + 102990831321.

It is an arithmetic number, because the mean of its divisors is an integer number (5355523223388).

Almost surely, 2^{21216111231011} is an apocalyptic number.

21216111231011 is a deficient number, since it is larger than the sum of its proper divisors (205981662541).

21216111231011 is a wasteful number, since it uses less digits than its factorization.

21216111231011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205981662540.

The product of its (nonzero) digits is 144, while the sum is 23.

Adding to 21216111231011 its reverse (11013211161212), we get a palindrome (32229322392223).

The spelling of 21216111231011 in words is "twenty-one trillion, two hundred sixteen billion, one hundred eleven million, two hundred thirty-one thousand, eleven".