665766 has 16 divisors (see below), whose sum is σ = 1479600. Its totient is φ = 221904.

The previous prime is 665761. The next prime is 665773. The reversal of 665766 is 667566.

It is a plaindrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 665766.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665761) by changing a digit.

665766 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6111 + ... + 6218.

It is an arithmetic number, because the mean of its divisors is an integer number (92475).

2⁶⁶⁵⁷⁶⁶ is an apocalyptic number.

665766 is an abundant number, since it is smaller than the sum of its proper divisors (813834).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665766 is a wasteful number, since it uses less digits than its factorization.

665766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12340 (or 12334 counting only the distinct ones).

The product of its digits is 45360, while the sum is 36.

The square root of 665766 is about 815.9448510776. The cubic root of 665766 is about 87.3186885038.

It can be divided in two parts, 665 and 766, that added together give a triangular number (1431 = T₅₃).

The spelling of 665766 in words is "six hundred sixty-five thousand, seven hundred sixty-six".