665161 has 8 divisors (see below), whose sum is σ = 766080. Its totient is φ = 565728.

The previous prime is 665153. The next prime is 665177. The reversal of 665161 is 161566.

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

It is a cyclic number.

It is not a de Polignac number, because 665161 - 2³ = 665153 is a prime.

It is a plaindrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (665111) 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, 885 + ... + 1453.

It is an arithmetic number, because the mean of its divisors is an integer number (95760).

2⁶⁶⁵¹⁶¹ is an apocalyptic number.

It is an amenable number.

665161 is a deficient number, since it is larger than the sum of its proper divisors (100919).

665161 is a wasteful number, since it uses less digits than its factorization.

665161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 743.

The product of its digits is 1080, while the sum is 25.

The square root of 665161 is about 815.5740309745. The cubic root of 665161 is about 87.2922308512.

The spelling of 665161 in words is "six hundred sixty-five thousand, one hundred sixty-one".