666361 has 4 divisors (see below), whose sum is σ = 672372. Its totient is φ = 660352.

The previous prime is 666353. The next prime is 666403. The reversal of 666361 is 163666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 281961 + 384400 = 531^2 + 620^2 .

It is a cyclic number.

It is not a de Polignac number, because 666361 - 2³ = 666353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666301) 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 in 3 ways as a sum of consecutive naturals, for example, 2836 + ... + 3061.

It is an arithmetic number, because the mean of its divisors is an integer number (168093).

2⁶⁶⁶³⁶¹ is an apocalyptic number.

It is an amenable number.

666361 is a deficient number, since it is larger than the sum of its proper divisors (6011).

666361 is a wasteful number, since it uses less digits than its factorization.

666361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6010.

The product of its digits is 3888, while the sum is 28.

The square root of 666361 is about 816.3093776259. The cubic root of 666361 is about 87.3446932112.

It can be divided in two parts, 6663 and 61, that added together give a square (6724 = 82²).

The spelling of 666361 in words is "six hundred sixty-six thousand, three hundred sixty-one".