665481 has 4 divisors (see below), whose sum is σ = 887312. Its totient is φ = 443652.

The previous prime is 665479. The next prime is 665501. The reversal of 665481 is 184566.

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 not a de Polignac number, because 665481 - 2¹ = 665479 is a prime.

It is a super-2 number, since 2×665481² = 885729922722, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (665381) 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, 110911 + ... + 110916.

It is an arithmetic number, because the mean of its divisors is an integer number (221828).

2⁶⁶⁵⁴⁸¹ is an apocalyptic number.

It is an amenable number.

665481 is a deficient number, since it is larger than the sum of its proper divisors (221831).

665481 is a wasteful number, since it uses less digits than its factorization.

665481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221830.

The product of its digits is 5760, while the sum is 30.

The square root of 665481 is about 815.7701882271. The cubic root of 665481 is about 87.3062269793.

The spelling of 665481 in words is "six hundred sixty-five thousand, four hundred eighty-one".