21010021100 has 18 divisors (see below), whose sum is σ = 45591746004. Its totient is φ = 8404008400.

The previous prime is 21010021091. The next prime is 21010021121. The reversal of 21010021100 is 112001012.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 105050006 + ... + 105050205.

It is an arithmetic number, because the mean of its divisors is an integer number (2532874778).

Almost surely, 2^21010021100 is an apocalyptic number.

21010021100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21010021100 is an abundant number, since it is smaller than the sum of its proper divisors (24581724904).

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

21010021100 is a wasteful number, since it uses less digits than its factorization.

21010021100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210100225 (or 210100218 counting only the distinct ones).

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

Adding to 21010021100 its reverse (112001012), we get a palindrome (21122022112).

The spelling of 21010021100 in words is "twenty-one billion, ten million, twenty-one thousand, one hundred".