665428 has 6 divisors (see below), whose sum is σ = 1164506. Its totient is φ = 332712.

The previous prime is 665419. The next prime is 665429. The reversal of 665428 is 824566.

It can be written as a sum of positive squares in only one way, i.e., 659344 + 6084 = 812^2 + 78^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 665428.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83175 + ... + 83182.

2⁶⁶⁵⁴²⁸ is an apocalyptic number.

It is an amenable number.

665428 is a deficient number, since it is larger than the sum of its proper divisors (499078).

665428 is a wasteful number, since it uses less digits than its factorization.

665428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166361 (or 166359 counting only the distinct ones).

The product of its digits is 11520, while the sum is 31.

The square root of 665428 is about 815.7377029413. The cubic root of 665428 is about 87.3039091806.

The spelling of 665428 in words is "six hundred sixty-five thousand, four hundred twenty-eight".