2001012100020 has 192 divisors, whose sum is σ = 6427370772480. Its totient is φ = 516295296000.

The previous prime is 2001012099991. The next prime is 2001012100097. The reversal of 2001012100020 is 200012101002.

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

It is a junction number, because it is equal to n+sod(n) for n = 2001012099975 and 2001012100011.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 165736704 + ... + 165748776.

It is an arithmetic number, because the mean of its divisors is an integer number (33475889440).

Almost surely, 2^{2001012100020} is an apocalyptic number.

2001012100020 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 2001012100020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3213685386240).

2001012100020 is an abundant number, since it is smaller than the sum of its proper divisors (4426358672460).

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

2001012100020 is a wasteful number, since it uses less digits than its factorization.

2001012100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22023 (or 22015 counting only the distinct ones).

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

Adding to 2001012100020 its reverse (200012101002), we get a palindrome (2201024201022).

The spelling of 2001012100020 in words is "two trillion, one billion, twelve million, one hundred thousand, twenty".