21011200100 has 144 divisors (see below), whose sum is σ = 50655507840. Its totient is φ = 7500979200.

The previous prime is 21011200081. The next prime is 21011200109. The reversal of 21011200100 is 100211012.

It is not an unprimeable number, because it can be changed into a prime (21011200109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 15369617 + ... + 15370983.

It is an arithmetic number, because the mean of its divisors is an integer number (351774360).

Almost surely, 2^21011200100 is an apocalyptic number.

21011200100 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 21011200100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25327753920).

21011200100 is an abundant number, since it is smaller than the sum of its proper divisors (29644307740).

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

21011200100 is a wasteful number, since it uses less digits than its factorization.

21011200100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1638 (or 1631 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21011200100 its reverse (100211012), we get a palindrome (21111411112).

The spelling of 21011200100 in words is "twenty-one billion, eleven million, two hundred thousand, one hundred".