21002100011100 has 432 divisors, whose sum is σ = 71135169120288. Its totient is φ = 5152176506880.

The previous prime is 21002100011089. The next prime is 21002100011107. The reversal of 21002100011100 is 111000120012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002100011107) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 4649566042 + ... + 4649570558.

It is an arithmetic number, because the mean of its divisors is an integer number (164664743334).

Almost surely, 2^{21002100011100} is an apocalyptic number.

21002100011100 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 21002100011100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35567584560144).

21002100011100 is an abundant number, since it is smaller than the sum of its proper divisors (50133069109188).

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

21002100011100 is a wasteful number, since it uses less digits than its factorization.

21002100011100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5814 (or 5804 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21002100011100 its reverse (111000120012), we get a palindrome (21113100131112).

The spelling of 21002100011100 in words is "twenty-one trillion, two billion, one hundred million, eleven thousand, one hundred".