21000100002020 has 96 divisors (see below), whose sum is σ = 45764974080000. Its totient is φ = 8084799894528.

The previous prime is 21000100001893. The next prime is 21000100002053. The reversal of 21000100002020 is 2020000100012.

It is a junction number, because it is equal to n+sod(n) for n = 21000100001989 and 21000100002007.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 341328821 + ... + 341390339.

It is an arithmetic number, because the mean of its divisors is an integer number (476718480000).

Almost surely, 2^{21000100002020} is an apocalyptic number.

21000100002020 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 21000100002020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22882487040000).

21000100002020 is an abundant number, since it is smaller than the sum of its proper divisors (24764874077980).

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

21000100002020 is a wasteful number, since it uses less digits than its factorization.

21000100002020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63405 (or 63403 counting only the distinct ones).

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

Adding to 21000100002020 its reverse (2020000100012), we get a palindrome (23020100102032).

The spelling of 21000100002020 in words is "twenty-one trillion, one hundred million, two thousand, twenty".