42566 has 4 divisors (see below), whose sum is σ = 63852. Its totient is φ = 21282.

The previous prime is 42557. The next prime is 42569. The reversal of 42566 is 66524.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42569) by changing a digit.

42566 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10640 + ... + 10643.

It is an arithmetic number, because the mean of its divisors is an integer number (15963).

2⁴²⁵⁶⁶ is an apocalyptic number.

42566 is a deficient number, since it is larger than the sum of its proper divisors (21286).

42566 is a wasteful number, since it uses less digits than its factorization.

42566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21285.

The product of its digits is 1440, while the sum is 23.

The square root of 42566 is about 206.3152926954. The cubic root of 42566 is about 34.9157155627.

The spelling of 42566 in words is "forty-two thousand, five hundred sixty-six".