665558 has 4 divisors (see below), whose sum is σ = 998340. Its totient is φ = 332778.

The previous prime is 665557. The next prime is 665563. The reversal of 665558 is 855566.

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

It is a super-3 number, since 3×665558³ = 884461592984763336, which contains 333 as substring.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665557) 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 as a sum of consecutive naturals, namely, 166388 + ... + 166391.

It is an arithmetic number, because the mean of its divisors is an integer number (249585).

2⁶⁶⁵⁵⁵⁸ is an apocalyptic number.

665558 is a deficient number, since it is larger than the sum of its proper divisors (332782).

665558 is a wasteful number, since it uses less digits than its factorization.

665558 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332781.

The product of its digits is 36000, while the sum is 35.

The square root of 665558 is about 815.8173815260. The cubic root of 665558 is about 87.3095941279.

The spelling of 665558 in words is "six hundred sixty-five thousand, five hundred fifty-eight".