21221201212110 has 192 divisors, whose sum is σ = 58050333918720. Its totient is φ = 5371189125120.

The previous prime is 21221201212109. The next prime is 21221201212117. The reversal of 21221201212110 is 1121210212212.

21221201212110 is a `hidden beast` number, since 21 + 221 + 201 + 212 + 1 + 10 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221201212117) by changing a digit.

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, 439001862 + ... + 439050198.

It is an arithmetic number, because the mean of its divisors is an integer number (302345489160).

Almost surely, 2^{21221201212110} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221201212110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29025166959360).

21221201212110 is an abundant number, since it is smaller than the sum of its proper divisors (36829132706610).

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

21221201212110 is a wasteful number, since it uses less digits than its factorization.

21221201212110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51403 (or 51400 counting only the distinct ones).

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

Adding to 21221201212110 its reverse (1121210212212), we get a palindrome (22342411424322).

The spelling of 21221201212110 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twelve thousand, one hundred ten".