2001221021020 has 192 divisors, whose sum is σ = 4671398946816. Its totient is φ = 715506462720.

The previous prime is 2001221021011. The next prime is 2001221021039. The reversal of 2001221021020 is 201201221002.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (13).

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, 1119876567 + ... + 1119878353.

It is an arithmetic number, because the mean of its divisors is an integer number (24330202848).

Almost surely, 2^{2001221021020} is an apocalyptic number.

2001221021020 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 2001221021020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2335699473408).

2001221021020 is an abundant number, since it is smaller than the sum of its proper divisors (2670177925796).

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

2001221021020 is a wasteful number, since it uses less digits than its factorization.

2001221021020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2780 (or 2778 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 2001221021020 its reverse (201201221002), we get a palindrome (2202422242022).

The spelling of 2001221021020 in words is "two trillion, one billion, two hundred twenty-one million, twenty-one thousand, twenty".