665471 has 4 divisors (see below), whose sum is σ = 681744. Its totient is φ = 649200.

The previous prime is 665447. The next prime is 665479. The reversal of 665471 is 174566.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 665471 - 2¹⁴ = 649087 is a prime.

It is a super-3 number, since 3×665471³ = 884114794806846333, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8075 + ... + 8156.

It is an arithmetic number, because the mean of its divisors is an integer number (170436).

2⁶⁶⁵⁴⁷¹ is an apocalyptic number.

665471 is a deficient number, since it is larger than the sum of its proper divisors (16273).

665471 is a wasteful number, since it uses less digits than its factorization.

665471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16272.

The product of its digits is 5040, while the sum is 29.

The square root of 665471 is about 815.7640590269. The cubic root of 665471 is about 87.3057896682.

The spelling of 665471 in words is "six hundred sixty-five thousand, four hundred seventy-one".