66865 has 8 divisors (see below), whose sum is σ = 82368. Its totient is φ = 52080.

The previous prime is 66863. The next prime is 66877. The reversal of 66865 is 56866.

66865 is nontrivially palindromic in base 6.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66865 - 2¹ = 66863 is a prime.

It is a Duffinian number.

66865 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60 + ... + 370.

It is an arithmetic number, because the mean of its divisors is an integer number (10296).

2⁶⁶⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

66865 is a deficient number, since it is larger than the sum of its proper divisors (15503).

66865 is a wasteful number, since it uses less digits than its factorization.

66865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359.

The product of its digits is 8640, while the sum is 31.

The square root of 66865 is about 258.5826753671. The cubic root of 66865 is about 40.5881836078.

Subtracting from 66865 its reverse (56866), we obtain a palindrome (9999).

The spelling of 66865 in words is "sixty-six thousand, eight hundred sixty-five".