21111222121110 has 192 divisors, whose sum is σ = 62040289409280. Its totient is φ = 4933704464640.

The previous prime is 21111222121063. The next prime is 21111222121151. The reversal of 21111222121110 is 1112122211112.

It is a happy number.

21111222121110 is a `hidden beast` number, since 211 + 1 + 1 + 222 + 121 + 110 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 17888737 + ... + 19032323.

It is an arithmetic number, because the mean of its divisors is an integer number (323126507340).

Almost surely, 2^{21111222121110} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21111222121110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31020144704640).

21111222121110 is an abundant number, since it is smaller than the sum of its proper divisors (40929067288170).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21111222121110 is a wasteful number, since it uses less digits than its factorization.

21111222121110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1144283 (or 1144280 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21111222121110 its reverse (1112122211112), we get a palindrome (22223344332222).

The spelling of 21111222121110 in words is "twenty-one trillion, one hundred eleven billion, two hundred twenty-two million, one hundred twenty-one thousand, one hundred ten".