667856 has 40 divisors (see below), whose sum is σ = 1517760. Its totient is φ = 278784.

The previous prime is 667837. The next prime is 667859. The reversal of 667856 is 658766.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667859) by changing a digit.

667856 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7460 + ... + 7548.

It is an arithmetic number, because the mean of its divisors is an integer number (37944).

2⁶⁶⁷⁸⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 667856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (758880).

667856 is an abundant number, since it is smaller than the sum of its proper divisors (849904).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

667856 is a wasteful number, since it uses less digits than its factorization.

667856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171 (or 165 counting only the distinct ones).

The product of its digits is 60480, while the sum is 38.

The square root of 667856 is about 817.2245713389. The cubic root of 667856 is about 87.4099645302.

The spelling of 667856 in words is "six hundred sixty-seven thousand, eight hundred fifty-six".