221021200000020 has 384 divisors, whose sum is σ = 710808311549952. Its totient is φ = 50267157811200.

The previous prime is 221021199999989. The next prime is 221021200000021. The reversal of 221021200000020 is 20000002120122.

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 = 221021199999951 and 221021200000005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221021200000021) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 135845850447 + ... + 135845852073.

It is an arithmetic number, because the mean of its divisors is an integer number (1851063311328).

Almost surely, 2^{221021200000020} is an apocalyptic number.

221021200000020 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 221021200000020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (355404155774976).

221021200000020 is an abundant number, since it is smaller than the sum of its proper divisors (489787111549932).

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

221021200000020 is a wasteful number, since it uses less digits than its factorization.

221021200000020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3711 (or 3709 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 221021200000020 its reverse (20000002120122), we get a palindrome (241021202120142).

The spelling of 221021200000020 in words is "two hundred twenty-one trillion, twenty-one billion, two hundred million, twenty", and thus it is an aban number.