665438 has 8 divisors (see below), whose sum is σ = 1002288. Its totient is φ = 331344.

The previous prime is 665429. The next prime is 665447. The reversal of 665438 is 834566.

It is an interprime number because it is at equal distance from previous prime (665429) and next prime (665447).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 665438.

It is an unprimeable number.

665438 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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, 95 + ... + 1157.

It is an arithmetic number, because the mean of its divisors is an integer number (125286).

2⁶⁶⁵⁴³⁸ is an apocalyptic number.

665438 is a deficient number, since it is larger than the sum of its proper divisors (336850).

665438 is a wasteful number, since it uses less digits than its factorization.

665438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1378.

The product of its digits is 17280, while the sum is 32.

The square root of 665438 is about 815.7438323395. The cubic root of 665438 is about 87.3043465105.

The spelling of 665438 in words is "six hundred sixty-five thousand, four hundred thirty-eight".