665501 has 2 divisors, whose sum is σ = 665502. Its totient is φ = 665500.

The previous prime is 665479. The next prime is 665503. The reversal of 665501 is 105566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 525625 + 139876 = 725^2 + 374^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665501 is a prime.

Together with 665503, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665503) 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, 332750 + 332751.

It is an arithmetic number, because the mean of its divisors is an integer number (332751).

2⁶⁶⁵⁵⁰¹ is an apocalyptic number.

It is an amenable number.

665501 is a deficient number, since it is larger than the sum of its proper divisors (1).

665501 is an equidigital number, since it uses as much as digits as its factorization.

665501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 665501 is about 815.7824464893. The cubic root of 665501 is about 87.3071015883.

The spelling of 665501 in words is "six hundred sixty-five thousand, five hundred one".