21001001010220 has 144 divisors (see below), whose sum is σ = 55404393327360. Its totient is φ = 6545364186240.

The previous prime is 21001001010167. The next prime is 21001001010289. The reversal of 21001001010220 is 2201010010012.

It is a super-2 number, since 2×21001001010220² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21001001010197 and 21001001010206.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 398724327 + ... + 398776993.

It is an arithmetic number, because the mean of its divisors is an integer number (384752731440).

Almost surely, 2^{21001001010220} is an apocalyptic number.

21001001010220 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 21001001010220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27702196663680).

21001001010220 is an abundant number, since it is smaller than the sum of its proper divisors (34403392317140).

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

21001001010220 is a wasteful number, since it uses less digits than its factorization.

21001001010220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76244 (or 76231 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21001001010220 its reverse (2201010010012), we get a palindrome (23202011020232).

The spelling of 21001001010220 in words is "twenty-one trillion, one billion, one million, ten thousand, two hundred twenty".