2001221021209 has 16 divisors (see below), whose sum is σ = 2090531963520. Its totient is φ = 1913267301120.

The previous prime is 2001221021179. The next prime is 2001221021213. The reversal of 2001221021209 is 9021201221002.

It is a cyclic number.

It is not a de Polignac number, because 2001221021209 - 2¹³ = 2001221013017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2001221021209.

It is not an unprimeable number, because it can be changed into a prime (2001221021309) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37971294 + ... + 38023960.

It is an arithmetic number, because the mean of its divisors is an integer number (130658247720).

Almost surely, 2^{2001221021209} is an apocalyptic number.

2001221021209 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

2001221021209 is a deficient number, since it is larger than the sum of its proper divisors (89310942311).

2001221021209 is a wasteful number, since it uses less digits than its factorization.

2001221021209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65520.

The product of its (nonzero) digits is 288, while the sum is 22.

The spelling of 2001221021209 in words is "two trillion, one billion, two hundred twenty-one million, twenty-one thousand, two hundred nine".