669181 has 2 divisors, whose sum is σ = 669182. Its totient is φ = 669180.

The previous prime is 669173. The next prime is 669241. The reversal of 669181 is 181966.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 443556 + 225625 = 666^2 + 475^2 .

It is a cyclic number.

It is not a de Polignac number, because 669181 - 2³ = 669173 is a prime.

It is a super-2 number, since 2×669181² = 895606421522, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334590 + 334591.

It is an arithmetic number, because the mean of its divisors is an integer number (334591).

2⁶⁶⁹¹⁸¹ is an apocalyptic number.

It is an amenable number.

669181 is a deficient number, since it is larger than the sum of its proper divisors (1).

669181 is an equidigital number, since it uses as much as digits as its factorization.

669181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 669181 is about 818.0348403338. The cubic root of 669181 is about 87.4677323197.

The spelling of 669181 in words is "six hundred sixty-nine thousand, one hundred eighty-one".