21000310020 has 96 divisors (see below), whose sum is σ = 65528736000. Its totient is φ = 5583416832.

The previous prime is 21000309991. The next prime is 21000310043. The reversal of 21000310020 is 2001300012.

It is a happy number.

It is a super-3 number, since 3×21000310020³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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

It is a junction number, because it is equal to n+sod(n) for n = 21000309984 and 21000310011.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 124281 + ... + 239679.

It is an arithmetic number, because the mean of its divisors is an integer number (682591000).

Almost surely, 2^21000310020 is an apocalyptic number.

21000310020 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 21000310020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32764368000).

21000310020 is an abundant number, since it is smaller than the sum of its proper divisors (44528425980).

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

21000310020 is a wasteful number, since it uses less digits than its factorization.

21000310020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115754 (or 115746 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

Adding to 21000310020 its reverse (2001300012), we get a palindrome (23001610032).

The spelling of 21000310020 in words is "twenty-one billion, three hundred ten thousand, twenty".