561221 has 4 divisors (see below), whose sum is σ = 594252. Its totient is φ = 528192.

The previous prime is 561199. The next prime is 561229. The reversal of 561221 is 122165.

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 264196 + 297025 = 514^2 + 545^2 .

It is a cyclic number.

It is not a de Polignac number, because 561221 - 2¹⁴ = 544837 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 33013 = 561221 / (5 + 6 + 1 + 2 + 2 + 1).

It is a self number, because there is not a number n which added to its sum of digits gives 561221.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 561221.

It is not an unprimeable number, because it can be changed into a prime (561229) 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, 16490 + ... + 16523.

It is an arithmetic number, because the mean of its divisors is an integer number (148563).

2⁵⁶¹²²¹ is an apocalyptic number.

It is an amenable number.

561221 is a deficient number, since it is larger than the sum of its proper divisors (33031).

561221 is a wasteful number, since it uses less digits than its factorization.

561221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33030.

The product of its digits is 120, while the sum is 17.

The square root of 561221 is about 749.1468480879. The cubic root of 561221 is about 82.4855683357.

Adding to 561221 its reverse (122165), we get a palindrome (683386).

The spelling of 561221 in words is "five hundred sixty-one thousand, two hundred twenty-one".