21010100221020 has 192 divisors, whose sum is σ = 60977567379456. Its totient is φ = 5399518095360.

The previous prime is 21010100221007. The next prime is 21010100221027. The reversal of 21010100221020 is 2012200101012.

It is a super-2 number, since 2×21010100221020² (a number of 27 digits) contains 22 as substring.

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 = 21010100220987 and 21010100221005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010100221027) 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, 1073193472 + ... + 1073213048.

It is an arithmetic number, because the mean of its divisors is an integer number (317591496768).

Almost surely, 2^{21010100221020} is an apocalyptic number.

21010100221020 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 21010100221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30488783689728).

21010100221020 is an abundant number, since it is smaller than the sum of its proper divisors (39967467158436).

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

21010100221020 is a wasteful number, since it uses less digits than its factorization.

21010100221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21980 (or 21978 counting only the distinct ones).

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

Adding to 21010100221020 its reverse (2012200101012), we get a palindrome (23022300322032).

The spelling of 21010100221020 in words is "twenty-one trillion, ten billion, one hundred million, two hundred twenty-one thousand, twenty".