2001221020 has 12 divisors (see below), whose sum is σ = 4202564184. Its totient is φ = 800488400.

The previous prime is 2001220987. The next prime is 2001221039. The reversal of 2001221020 is 201221002.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 2001220988 and 2001221006.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50030506 + ... + 50030545.

It is an arithmetic number, because the mean of its divisors is an integer number (350213682).

Almost surely, 2^2001221020 is an apocalyptic number.

2001221020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2001221020 is an abundant number, since it is smaller than the sum of its proper divisors (2201343164).

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

2001221020 is a wasteful number, since it uses less digits than its factorization.

2001221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100061060 (or 100061058 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 2001221020 is about 44735.0088856591. The cubic root of 2001221020 is about 1260.1773958681.

Adding to 2001221020 its reverse (201221002), we get a palindrome (2202442022).

The spelling of 2001221020 in words is "two billion, one million, two hundred twenty-one thousand, twenty".