42666665 has 4 divisors (see below), whose sum is σ = 51200004. Its totient is φ = 34133328.

The previous prime is 42666641. The next prime is 42666667. The reversal of 42666665 is 56666624.

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 9339136 + 33327529 = 3056^2 + 5773^2 .

It is a cyclic number.

It is not a de Polignac number, because 42666665 - 2⁶ = 42666601 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (42666667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4266662 + ... + 4266671.

It is an arithmetic number, because the mean of its divisors is an integer number (12800001).

Almost surely, 2^42666665 is an apocalyptic number.

It is an amenable number.

42666665 is a deficient number, since it is larger than the sum of its proper divisors (8533339).

42666665 is an equidigital number, since it uses as much as digits as its factorization.

42666665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8533338.

The product of its digits is 311040, while the sum is 41.

The square root of 42666665 is about 6531.9725198442. The cubic root of 42666665 is about 349.4321813446.

Subtracting from 42666665 its sum of digits (41), we obtain a palindrome (42666624).

The spelling of 42666665 in words is "forty-two million, six hundred sixty-six thousand, six hundred sixty-five".