20001220443220 has 192 divisors, whose sum is σ = 44643612754944. Its totient is φ = 7511474995200.

The previous prime is 20001220443179. The next prime is 20001220443233. The reversal of 20001220443220 is 2234402210002.

It is a junction number, because it is equal to n+sod(n) for n = 20001220443191 and 20001220443200.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6773185264 + ... + 6773188216.

It is an arithmetic number, because the mean of its divisors is an integer number (232518816432).

Almost surely, 2^{20001220443220} is an apocalyptic number.

20001220443220 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 20001220443220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22321806377472).

20001220443220 is an abundant number, since it is smaller than the sum of its proper divisors (24642392311724).

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

20001220443220 is a wasteful number, since it uses less digits than its factorization.

20001220443220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3962 (or 3960 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 20001220443220 its reverse (2234402210002), we get a palindrome (22235622653222).

The spelling of 20001220443220 in words is "twenty trillion, one billion, two hundred twenty million, four hundred forty-three thousand, two hundred twenty".