667581 has 4 divisors (see below), whose sum is σ = 890112. Its totient is φ = 445052.

The previous prime is 667577. The next prime is 667631. The reversal of 667581 is 185766.

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 667581 - 2² = 667577 is a prime.

It is a super-2 number, since 2×667581² = 891328783122, which contains 22 as substring.

It is a D-number.

It is a plaindrome in base 9.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 667581.

It is not an unprimeable number, because it can be changed into a prime (667501) 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 in 3 ways as a sum of consecutive naturals, for example, 111261 + ... + 111266.

It is an arithmetic number, because the mean of its divisors is an integer number (222528).

2⁶⁶⁷⁵⁸¹ is an apocalyptic number.

It is an amenable number.

667581 is a deficient number, since it is larger than the sum of its proper divisors (222531).

667581 is a wasteful number, since it uses less digits than its factorization.

667581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222530.

The product of its digits is 10080, while the sum is 33.

The square root of 667581 is about 817.0563016096. The cubic root of 667581 is about 87.3979654165.

The spelling of 667581 in words is "six hundred sixty-seven thousand, five hundred eighty-one".