20011001220 has 216 divisors, whose sum is σ = 71666247744. Its totient is φ = 4505542272.

The previous prime is 20011001173. The next prime is 20011001249. The reversal of 20011001220 is 2210011002.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 574009 + ... + 607871.

It is an arithmetic number, because the mean of its divisors is an integer number (331788184).

Almost surely, 2^20011001220 is an apocalyptic number.

20011001220 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 20011001220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35833123872).

20011001220 is an abundant number, since it is smaller than the sum of its proper divisors (51655246524).

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

20011001220 is a wasteful number, since it uses less digits than its factorization.

20011001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33959 (or 33947 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 20011001220 its reverse (2210011002), we get a palindrome (22221012222).

The spelling of 20011001220 in words is "twenty billion, eleven million, one thousand, two hundred twenty".