221021211209 has 4 divisors (see below), whose sum is σ = 226411972500. Its totient is φ = 215630449920.

The previous prime is 221021211161. The next prime is 221021211211. The reversal of 221021211209 is 902112120122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 97066518025 + 123954693184 = 311555^2 + 352072^2 .

It is a cyclic number.

It is not a de Polignac number, because 221021211209 - 2⁸ = 221021210953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221021211259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2695380584 + ... + 2695380665.

It is an arithmetic number, because the mean of its divisors is an integer number (56602993125).

Almost surely, 2^221021211209 is an apocalyptic number.

It is an amenable number.

221021211209 is a deficient number, since it is larger than the sum of its proper divisors (5390761291).

221021211209 is an equidigital number, since it uses as much as digits as its factorization.

221021211209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5390761290.

The product of its (nonzero) digits is 288, while the sum is 23.

The spelling of 221021211209 in words is "two hundred twenty-one billion, twenty-one million, two hundred eleven thousand, two hundred nine".