21221111021209 has 16 divisors (see below), whose sum is σ = 23298217047360. Its totient is φ = 19168662202560.

The previous prime is 21221111021191. The next prime is 21221111021213. The reversal of 21221111021209 is 90212011112212.

It is a cyclic number.

It is not a de Polignac number, because 21221111021209 - 2⁵ = 21221111021177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221111021309) 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, 124350262 + ... + 124520800.

It is an arithmetic number, because the mean of its divisors is an integer number (1456138565460).

Almost surely, 2^{21221111021209} is an apocalyptic number.

It is an amenable number.

21221111021209 is a deficient number, since it is larger than the sum of its proper divisors (2077106026151).

21221111021209 is a wasteful number, since it uses less digits than its factorization.

21221111021209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242760.

The product of its (nonzero) digits is 288, while the sum is 25.

The spelling of 21221111021209 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, twenty-one thousand, two hundred nine".