667813 has 4 divisors (see below), whose sum is σ = 685900. Its totient is φ = 649728.

The previous prime is 667801. The next prime is 667817. The reversal of 667813 is 318766.

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 588289 + 79524 = 767^2 + 282^2 .

It is a cyclic number.

It is not a de Polignac number, because 667813 - 2⁵ = 667781 is a prime.

It is a Duffinian number.

667813 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667817) 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, 8988 + ... + 9061.

It is an arithmetic number, because the mean of its divisors is an integer number (171475).

2⁶⁶⁷⁸¹³ is an apocalyptic number.

It is an amenable number.

667813 is a deficient number, since it is larger than the sum of its proper divisors (18087).

667813 is a wasteful number, since it uses less digits than its factorization.

667813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18086.

The product of its digits is 6048, while the sum is 31.

The square root of 667813 is about 817.1982623574. The cubic root of 667813 is about 87.4080885224.

The spelling of 667813 in words is "six hundred sixty-seven thousand, eight hundred thirteen".