665461 has 4 divisors (see below), whose sum is σ = 676800. Its totient is φ = 654124.

The previous prime is 665447. The next prime is 665479. The reversal of 665461 is 164566.

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 665461 - 2⁵ = 665429 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5581 + ... + 5698.

It is an arithmetic number, because the mean of its divisors is an integer number (169200).

2⁶⁶⁵⁴⁶¹ is an apocalyptic number.

It is an amenable number.

665461 is a deficient number, since it is larger than the sum of its proper divisors (11339).

665461 is a wasteful number, since it uses less digits than its factorization.

665461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11338.

The product of its digits is 4320, while the sum is 28.

The square root of 665461 is about 815.7579297806. The cubic root of 665461 is about 87.3053523527.

The spelling of 665461 in words is "six hundred sixty-five thousand, four hundred sixty-one".