2001221100 has 72 divisors (see below), whose sum is σ = 6433563920. Its totient is φ = 533658240.

The previous prime is 2001221077. The next prime is 2001221119. The reversal of 2001221100 is 11221002.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 367897 + ... + 373296.

Almost surely, 2^2001221100 is an apocalyptic number.

2001221100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2001221100 is an abundant number, since it is smaller than the sum of its proper divisors (4432342820).

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

2001221100 is a wasteful number, since it uses less digits than its factorization.

2001221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 741216 (or 741203 counting only the distinct ones).

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

The square root of 2001221100 is about 44735.0097798134. The cubic root of 2001221100 is about 1260.1774126602.

Adding to 2001221100 its reverse (11221002), we get a palindrome (2012442102).

The spelling of 2001221100 in words is "two billion, one million, two hundred twenty-one thousand, one hundred".