667646 has 16 divisors (see below), whose sum is σ = 1158144. Its totient is φ = 282744.

The previous prime is 667643. The next prime is 667649. The reversal of 667646 is 646766.

It is an interprime number because it is at equal distance from previous prime (667643) and next prime (667649).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1211 + ... + 1673.

It is an arithmetic number, because the mean of its divisors is an integer number (72384).

2⁶⁶⁷⁶⁴⁶ is an apocalyptic number.

667646 is a deficient number, since it is larger than the sum of its proper divisors (490498).

667646 is a wasteful number, since it uses less digits than its factorization.

667646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 575.

The product of its digits is 36288, while the sum is 35.

The square root of 667646 is about 817.0960775821. The cubic root of 667646 is about 87.4008018680.

The spelling of 667646 in words is "six hundred sixty-seven thousand, six hundred forty-six".