21221212211100 has 324 divisors, whose sum is σ = 74352642141960. Its totient is φ = 5057339232000.

The previous prime is 21221212211047. The next prime is 21221212211113. The reversal of 21221212211100 is 111221212212.

21221212211100 is a `hidden beast` number, since 21 + 221 + 212 + 211 + 1 + 0 + 0 = 666.

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

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 107 ways as a sum of consecutive naturals, for example, 4773670 + ... + 8076530.

Almost surely, 2^{21221212211100} is an apocalyptic number.

21221212211100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221212211100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37176321070980).

21221212211100 is an abundant number, since it is smaller than the sum of its proper divisors (53131429930860).

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

21221212211100 is a wasteful number, since it uses less digits than its factorization.

21221212211100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3302962 (or 3302941 counting only the distinct ones).

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

Adding to 21221212211100 its reverse (111221212212), we get a palindrome (21332433423312).

The spelling of 21221212211100 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twelve million, two hundred eleven thousand, one hundred".