21010020000 has 240 divisors, whose sum is σ = 69619489632. Its totient is φ = 5545600000.

The previous prime is 21010019999. The next prime is 21010020007. The reversal of 21010020000 is 2001012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is not an unprimeable number, because it can be changed into a prime (21010020007) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 6058267 + ... + 6061733.

Almost surely, 2^21010020000 is an apocalyptic number.

21010020000 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 21010020000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34809744816).

21010020000 is an abundant number, since it is smaller than the sum of its proper divisors (48609469632).

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

21010020000 is a wasteful number, since it uses less digits than its factorization.

21010020000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3601 (or 3578 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

Adding to 21010020000 its reverse (2001012), we get a palindrome (21012021012).

The spelling of 21010020000 in words is "twenty-one billion, ten million, twenty thousand".