665101 has 4 divisors (see below), whose sum is σ = 673600. Its totient is φ = 656604.

The previous prime is 665089. The next prime is 665111. The reversal of 665101 is 101566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 665101 - 2⁵ = 665069 is a prime.

It is a Duffinian number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 4131 + ... + 4288.

It is an arithmetic number, because the mean of its divisors is an integer number (168400).

2⁶⁶⁵¹⁰¹ is an apocalyptic number.

It is an amenable number.

665101 is a deficient number, since it is larger than the sum of its proper divisors (8499).

665101 is an equidigital number, since it uses as much as digits as its factorization.

665101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8498.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 665101 is about 815.5372462371. The cubic root of 665101 is about 87.2896060775.

Adding to 665101 its product of nonzero digits (180), we get a triangular number (665281 = T₁₁₅₃).

Adding to 665101 its reverse (101566), we get a palindrome (766667).

The spelling of 665101 in words is "six hundred sixty-five thousand, one hundred one".