21221220121110 has 24 divisors (see below), whose sum is σ = 55175172315120. Its totient is φ = 5658992032272.

The previous prime is 21221220121093. The next prime is 21221220121121. The reversal of 21221220121110 is 1112102212212.

21221220121110 is a `hidden beast` number, since 2 + 1 + 221 + 220 + 1 + 211 + 10 = 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 11 ways as a sum of consecutive naturals, for example, 117895667250 + ... + 117895667429.

It is an arithmetic number, because the mean of its divisors is an integer number (2298965513130).

Almost surely, 2^{21221220121110} is an apocalyptic number.

21221220121110 is an abundant number, since it is smaller than the sum of its proper divisors (33953952194010).

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

21221220121110 is a wasteful number, since it uses less digits than its factorization.

21221220121110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235791334692 (or 235791334689 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21221220121110 its reverse (1112102212212), we get a palindrome (22333322333322).

The spelling of 21221220121110 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty million, one hundred twenty-one thousand, one hundred ten".