221011209 has 12 divisors (see below), whose sum is σ = 333118656. Its totient is φ = 140934552.

The previous prime is 221011201. The next prime is 221011243. The reversal of 221011209 is 902110122.

It is not a de Polignac number, because 221011209 - 2³ = 221011201 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221011191 and 221011200.

It is not an unprimeable number, because it can be changed into a prime (221011201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 533637 + ... + 534050.

It is an arithmetic number, because the mean of its divisors is an integer number (27759888).

Almost surely, 2^221011209 is an apocalyptic number.

It is an amenable number.

221011209 is a deficient number, since it is larger than the sum of its proper divisors (112107447).

221011209 is a wasteful number, since it uses less digits than its factorization.

221011209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1067716 (or 1067713 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 221011209 is about 14866.4457420057. The cubic root of 221011209 is about 604.6045809943.

The spelling of 221011209 in words is "two hundred twenty-one million, eleven thousand, two hundred nine".