665653 has 4 divisors (see below), whose sum is σ = 668448. Its totient is φ = 662860.

The previous prime is 665633. The next prime is 665659. The reversal of 665653 is 356566.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 665653 - 2⁹ = 665141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665659) 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, 1003 + ... + 1528.

It is an arithmetic number, because the mean of its divisors is an integer number (167112).

2⁶⁶⁵⁶⁵³ is an apocalyptic number.

It is an amenable number.

665653 is a deficient number, since it is larger than the sum of its proper divisors (2795).

665653 is a wasteful number, since it uses less digits than its factorization.

665653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2794.

The product of its digits is 16200, while the sum is 31.

The square root of 665653 is about 815.8756032631. The cubic root of 665653 is about 87.3137480442.

The spelling of 665653 in words is "six hundred sixty-five thousand, six hundred fifty-three".