20111221100100 has 144 divisors (see below), whose sum is σ = 62679003787008. Its totient is φ = 4949308815360.

The previous prime is 20111221100099. The next prime is 20111221100107. The reversal of 20111221100100 is 100112211102.

It is a super-2 number, since 2×20111221100100² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (20111221100107) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16319797 + ... + 17508803.

It is an arithmetic number, because the mean of its divisors is an integer number (435270859632).

Almost surely, 2^{20111221100100} is an apocalyptic number.

20111221100100 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 20111221100100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31339501893504).

20111221100100 is an abundant number, since it is smaller than the sum of its proper divisors (42567782686908).

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

20111221100100 is a wasteful number, since it uses less digits than its factorization.

20111221100100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1193374 (or 1193367 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 20111221100100 its reverse (100112211102), we get a palindrome (20211333311202).

The spelling of 20111221100100 in words is "twenty trillion, one hundred eleven billion, two hundred twenty-one million, one hundred thousand, one hundred".