21212216615411 has 4 divisors (see below), whose sum is σ = 21943672360800. Its totient is φ = 20480760870024.

The previous prime is 21212216615393. The next prime is 21212216615501. The reversal of 21212216615411 is 11451661221212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21212216615411 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212216615011) 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, 365727872651 + ... + 365727872708.

It is an arithmetic number, because the mean of its divisors is an integer number (5485918090200).

Almost surely, 2^{21212216615411} is an apocalyptic number.

21212216615411 is a deficient number, since it is larger than the sum of its proper divisors (731455745389).

21212216615411 is an equidigital number, since it uses as much as digits as its factorization.

21212216615411 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 731455745388.

The product of its digits is 11520, while the sum is 35.

Adding to 21212216615411 its reverse (11451661221212), we get a palindrome (32663877836623).

The spelling of 21212216615411 in words is "twenty-one trillion, two hundred twelve billion, two hundred sixteen million, six hundred fifteen thousand, four hundred eleven".