21001110020 has 144 divisors (see below), whose sum is σ = 52989406848. Its totient is φ = 6919672320.

The previous prime is 21001109999. The next prime is 21001110103. The reversal of 21001110020 is 2001110012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1820912 + ... + 1832408.

It is an arithmetic number, because the mean of its divisors is an integer number (367981992).

Almost surely, 2^21001110020 is an apocalyptic number.

21001110020 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 21001110020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26494703424).

21001110020 is an abundant number, since it is smaller than the sum of its proper divisors (31988296828).

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

21001110020 is a wasteful number, since it uses less digits than its factorization.

21001110020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11578 (or 11557 counting only the distinct ones).

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

Adding to 21001110020 its reverse (2001110012), we get a palindrome (23002220032).

The spelling of 21001110020 in words is "twenty-one billion, one million, one hundred ten thousand, twenty".