21100200020100 has 108 divisors (see below), whose sum is σ = 66143476116900. Its totient is φ = 5626203475200.

The previous prime is 21100200020057. The next prime is 21100200020101. The reversal of 21100200020100 is 102000200112.

It can be written as a sum of positive squares in 6 ways, for example, as 2290700412036 + 18809499608064 = 1513506^2 + 4336992^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21100200020101) 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 35 ways as a sum of consecutive naturals, for example, 8783470 + ... + 10924730.

It is an arithmetic number, because the mean of its divisors is an integer number (612439593675).

Almost surely, 2^{21100200020100} is an apocalyptic number.

21100200020100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100200020100 is an abundant number, since it is smaller than the sum of its proper divisors (45043276096800).

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

21100200020100 is a wasteful number, since it uses less digits than its factorization.

21100200020100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2152230 (or 2152220 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21100200020100 its reverse (102000200112), we get a palindrome (21202200220212).

The spelling of 21100200020100 in words is "twenty-one trillion, one hundred billion, two hundred million, twenty thousand, one hundred".