21220111001209 has 8 divisors (see below), whose sum is σ = 21689565520392. Its totient is φ = 20753214817920.

The previous prime is 21220111001191. The next prime is 21220111001267. The reversal of 21220111001209 is 90210011102212.

It can be written as a sum of positive squares in 4 ways, for example, as 283446565609 + 20936664435600 = 532397^2 + 4575660^2 .

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 21220111001209 - 2¹⁹ = 21220110476921 is a prime.

It is a super-2 number, since 2×21220111001209² (a number of 27 digits) contains 22 as substring.

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 21220111001209.

It is not an unprimeable number, because it can be changed into a prime (21220111007209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 639567202 + ... + 639600379.

It is an arithmetic number, because the mean of its divisors is an integer number (2711195690049).

Almost surely, 2^{21220111001209} is an apocalyptic number.

It is an amenable number.

21220111001209 is a deficient number, since it is larger than the sum of its proper divisors (469454519183).

21220111001209 is a wasteful number, since it uses less digits than its factorization.

21220111001209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1279167947.

The product of its (nonzero) digits is 144, while the sum is 22.

The spelling of 21220111001209 in words is "twenty-one trillion, two hundred twenty billion, one hundred eleven million, one thousand, two hundred nine".