667213685 has 4 divisors (see below), whose sum is σ = 800656428. Its totient is φ = 533770944.

The previous prime is 667213681. The next prime is 667213691. The reversal of 667213685 is 586312766.

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 356114641 + 311099044 = 18871^2 + 17638^2 .

It is a cyclic number.

It is not a de Polignac number, because 667213685 - 2² = 667213681 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667213681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66721364 + ... + 66721373.

It is an arithmetic number, because the mean of its divisors is an integer number (200164107).

Almost surely, 2^667213685 is an apocalyptic number.

It is an amenable number.

667213685 is a deficient number, since it is larger than the sum of its proper divisors (133442743).

667213685 is a wasteful number, since it uses less digits than its factorization.

667213685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133442742.

The product of its digits is 362880, while the sum is 44.

The square root of 667213685 is about 25830.4797671278. The cubic root of 667213685 is about 873.8193316808.

The spelling of 667213685 in words is "six hundred sixty-seven million, two hundred thirteen thousand, six hundred eighty-five".