21001221001209 has 8 divisors (see below), whose sum is σ = 28529960605632. Its totient is φ = 13736647698800.

The previous prime is 21001221001207. The next prime is 21001221001213. The reversal of 21001221001209 is 90210012210012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21001221001209 - 2¹ = 21001221001207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21001221001207) 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, 66041575317 + ... + 66041575634.

It is an arithmetic number, because the mean of its divisors is an integer number (3566245075704).

Almost surely, 2^{21001221001209} is an apocalyptic number.

It is an amenable number.

21001221001209 is a deficient number, since it is larger than the sum of its proper divisors (7528739604423).

21001221001209 is a wasteful number, since it uses less digits than its factorization.

21001221001209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132083151007.

The product of its (nonzero) digits is 144, while the sum is 21.

The spelling of 21001221001209 in words is "twenty-one trillion, one billion, two hundred twenty-one million, one thousand, two hundred nine".