561166 has 4 divisors (see below), whose sum is σ = 841752. Its totient is φ = 280582.

The previous prime is 561161. The next prime is 561173. The reversal of 561166 is 661165.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 661165 = 5 ⋅132233.

It is a self number, because there is not a number n which added to its sum of digits gives 561166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140290 + ... + 140293.

It is an arithmetic number, because the mean of its divisors is an integer number (210438).

2⁵⁶¹¹⁶⁶ is an apocalyptic number.

561166 is a deficient number, since it is larger than the sum of its proper divisors (280586).

561166 is a wasteful number, since it uses less digits than its factorization.

561166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280585.

The product of its digits is 1080, while the sum is 25.

The square root of 561166 is about 749.1101387647. The cubic root of 561166 is about 82.4828737024.

Subtracting 561166 from its reverse (661165), we obtain a palindrome (99999).

It can be divided in two parts, 561 and 166, that added together give a palindrome (727).

The spelling of 561166 in words is "five hundred sixty-one thousand, one hundred sixty-six".