21000111221211 has 8 divisors (see below), whose sum is σ = 28003299016704. Its totient is φ = 13998498786600.

The previous prime is 21000111221203. The next prime is 21000111221263. The reversal of 21000111221211 is 11212211100012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21000111221211 - 2³ = 21000111221203 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21000111221911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 393809115 + ... + 393862436.

It is an arithmetic number, because the mean of its divisors is an integer number (3500412377088).

Almost surely, 2^{21000111221211} is an apocalyptic number.

21000111221211 is a deficient number, since it is larger than the sum of its proper divisors (7003187795493).

21000111221211 is an equidigital number, since it uses as much as digits as its factorization.

21000111221211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 787680441.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21000111221211 its reverse (11212211100012), we get a palindrome (32212322321223).

The spelling of 21000111221211 in words is "twenty-one trillion, one hundred eleven million, two hundred twenty-one thousand, two hundred eleven".