665769 has 16 divisors (see below), whose sum is σ = 980672. Its totient is φ = 399168.

The previous prime is 665761. The next prime is 665773. The reversal of 665769 is 967566.

It is a happy number.

It is not a de Polignac number, because 665769 - 2³ = 665761 is a prime.

It is a super-2 number, since 2×665769² = 886496722722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

665769 is a lucky number.

It is a plaindrome in base 14.

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

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1479 + ... + 1875.

It is an arithmetic number, because the mean of its divisors is an integer number (61292).

2⁶⁶⁵⁷⁶⁹ is an apocalyptic number.

It is an amenable number.

665769 is a deficient number, since it is larger than the sum of its proper divisors (314903).

665769 is a wasteful number, since it uses less digits than its factorization.

665769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456.

The product of its digits is 68040, while the sum is 39.

The square root of 665769 is about 815.9466894350. The cubic root of 665769 is about 87.3188196589.

665769 divided by its sum of digits (39) gives a palindrome (17071).

The spelling of 665769 in words is "six hundred sixty-five thousand, seven hundred sixty-nine".