2117221 has 4 divisors (see below), whose sum is σ = 2141100. Its totient is φ = 2093344.

The previous prime is 2117179. The next prime is 2117233. The reversal of 2117221 is 1227112.

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 390625 + 1726596 = 625^2 + 1314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2117221 is a prime.

It is a Duffinian number.

2117221 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 2117195 and 2117204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2117321) 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, 11806 + ... + 11983.

It is an arithmetic number, because the mean of its divisors is an integer number (535275).

2^2117221 is an apocalyptic number.

It is an amenable number.

2117221 is a deficient number, since it is larger than the sum of its proper divisors (23879).

2117221 is an equidigital number, since it uses as much as digits as its factorization.

2117221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23878.

The product of its digits is 56, while the sum is 16.

The square root of 2117221 is about 1455.0673523930. The cubic root of 2117221 is about 128.4070092867.

The spelling of 2117221 in words is "two million, one hundred seventeen thousand, two hundred twenty-one".