2217121 has 3 divisors (see below), whose sum is σ = 2218611. Its totient is φ = 2215632.

The previous prime is 2217113. The next prime is 2217143. The reversal of 2217121 is 1217122.

The square root of 2217121 is 1489.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 474721 + 1742400 = 689^2 + 1320^2 .

It is not a de Polignac number, because 2217121 - 2³ = 2217113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2217095 and 2217104.

It is not an unprimeable number, because it can be changed into a prime (2217101) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 745 + ... + 2233.

It is an arithmetic number, because the mean of its divisors is an integer number (739537).

2^2217121 is an apocalyptic number.

2217121 is the 1489-th square number.

2217121 is the 745-th centered octagonal number.

It is an amenable number.

2217121 is a deficient number, since it is larger than the sum of its proper divisors (1490).

2217121 is an frugal number, since it uses more digits than its factorization.

2217121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2978 (or 1489 counting only the distinct ones).

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

The cubic root of 2217121 is about 130.3956584864.

Multiplying 2217121 by its sum of digits (16), we get a square (35473936 = 5956²).

Subtracting from 2217121 its reverse (1217122), we obtain a palindrome (999999).

The spelling of 2217121 in words is "two million, two hundred seventeen thousand, one hundred twenty-one".