21115666514411 has 4 divisors (see below), whose sum is σ = 24132190302192. Its totient is φ = 18099142726632.

The previous prime is 21115666514377. The next prime is 21115666514461. The reversal of 21115666514411 is 11441566651112.

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 21115666514411 - 2¹⁸ = 21115666252267 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21115666514461) 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, 1508261893880 + ... + 1508261893893.

It is an arithmetic number, because the mean of its divisors is an integer number (6033047575548).

Almost surely, 2^{21115666514411} is an apocalyptic number.

21115666514411 is a deficient number, since it is larger than the sum of its proper divisors (3016523787781).

21115666514411 is an equidigital number, since it uses as much as digits as its factorization.

21115666514411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3016523787780.

The product of its digits is 172800, while the sum is 44.

The spelling of 21115666514411 in words is "twenty-one trillion, one hundred fifteen billion, six hundred sixty-six million, five hundred fourteen thousand, four hundred eleven".