665243 has 4 divisors (see below), whose sum is σ = 675240. Its totient is φ = 655248.

The previous prime is 665239. The next prime is 665251. The reversal of 665243 is 342566.

665243 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 665243 - 2² = 665239 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (665213) 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, 4898 + ... + 5031.

It is an arithmetic number, because the mean of its divisors is an integer number (168810).

2⁶⁶⁵²⁴³ is an apocalyptic number.

665243 is a deficient number, since it is larger than the sum of its proper divisors (9997).

665243 is an equidigital number, since it uses as much as digits as its factorization.

665243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9996.

The product of its digits is 4320, while the sum is 26.

The square root of 665243 is about 815.6243007660. The cubic root of 665243 is about 87.2958177867.

The spelling of 665243 in words is "six hundred sixty-five thousand, two hundred forty-three".