21100211020 has 96 divisors (see below), whose sum is σ = 51860551680. Its totient is φ = 7060919040.

The previous prime is 21100211009. The next prime is 21100211029. The reversal of 21100211020 is 2011200112.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21100210988 and 21100211006.

It is not an unprimeable number, because it can be changed into a prime (21100211029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2489590 + ... + 2498050.

It is an arithmetic number, because the mean of its divisors is an integer number (540214080).

Almost surely, 2^21100211020 is an apocalyptic number.

21100211020 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 21100211020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25930275840).

21100211020 is an abundant number, since it is smaller than the sum of its proper divisors (30760340660).

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

21100211020 is a wasteful number, since it uses less digits than its factorization.

21100211020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8903 (or 8901 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21100211020 its reverse (2011200112), we get a palindrome (23111411132).

The spelling of 21100211020 in words is "twenty-one billion, one hundred million, two hundred eleven thousand, twenty".