2001221988 has 24 divisors (see below), whose sum is σ = 4820148480. Its totient is φ = 645555360.

The previous prime is 2001221983. The next prime is 2001222001. The reversal of 2001221988 is 8891221002.

It is not an unprimeable number, because it can be changed into a prime (2001221983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2689443 + ... + 2690186.

It is an arithmetic number, because the mean of its divisors is an integer number (200839520).

Almost surely, 2^2001221988 is an apocalyptic number.

It is an amenable number.

2001221988 is an abundant number, since it is smaller than the sum of its proper divisors (2818926492).

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

2001221988 is a wasteful number, since it uses less digits than its factorization.

2001221988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5379667 (or 5379665 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 2001221988 is about 44735.0197049247. The cubic root of 2001221988 is about 1260.1775990526.

The spelling of 2001221988 in words is "two billion, one million, two hundred twenty-one thousand, nine hundred eighty-eight".