21210020110020 has 192 divisors, whose sum is σ = 68548198957056. Its totient is φ = 4799732889600.

The previous prime is 21210020110003. The next prime is 21210020110021. The reversal of 21210020110020 is 2001102001212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21210020109978 and 21210020110005.

It is not an unprimeable number, because it can be changed into a prime (21210020110021) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 178474620 + ... + 178593420.

It is an arithmetic number, because the mean of its divisors is an integer number (357021869568).

Almost surely, 2^{21210020110020} is an apocalyptic number.

21210020110020 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 21210020110020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34274099478528).

21210020110020 is an abundant number, since it is smaller than the sum of its proper divisors (47338178847036).

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

21210020110020 is a wasteful number, since it uses less digits than its factorization.

21210020110020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123050 (or 123048 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21210020110020 its reverse (2001102001212), we get a palindrome (23211122111232).

The spelling of 21210020110020 in words is "twenty-one trillion, two hundred ten billion, twenty million, one hundred ten thousand, twenty".