665407 has 4 divisors (see below), whose sum is σ = 667080. Its totient is φ = 663736.

The previous prime is 665387. The next prime is 665419. The reversal of 665407 is 704566.

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 665407 - 2⁷ = 665279 is a prime.

It is a Duffinian number.

665407 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665447) 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, 144 + ... + 1162.

It is an arithmetic number, because the mean of its divisors is an integer number (166770).

2⁶⁶⁵⁴⁰⁷ is an apocalyptic number.

665407 is a deficient number, since it is larger than the sum of its proper divisors (1673).

665407 is a wasteful number, since it uses less digits than its factorization.

665407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1672.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 665407 is about 815.7248310552. The cubic root of 665407 is about 87.3029907735.

The spelling of 665407 in words is "six hundred sixty-five thousand, four hundred seven".