2001221220 has 48 divisors (see below), whose sum is σ = 5754869568. Its totient is φ = 519235200.

The previous prime is 2001221203. The next prime is 2001221239. The reversal of 2001221220 is 221221002.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 2001221196 and 2001221205.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 448506 + ... + 452945.

It is an arithmetic number, because the mean of its divisors is an integer number (119893116).

Almost surely, 2^2001221220 is an apocalyptic number.

2001221220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2001221220 is an abundant number, since it is smaller than the sum of its proper divisors (3753648348).

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

2001221220 is a wasteful number, since it uses less digits than its factorization.

2001221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 901500 (or 901498 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 2001221220 is about 44735.0111210448. The cubic root of 2001221220 is about 1260.1774378484.

Adding to 2001221220 its reverse (221221002), we get a palindrome (2222442222).

The spelling of 2001221220 in words is "two billion, one million, two hundred twenty-one thousand, two hundred twenty".