667656 has 64 divisors (see below), whose sum is σ = 2030400. Its totient is φ = 201600.

The previous prime is 667649. The next prime is 667657. The reversal of 667656 is 656766.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 667656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667657) by changing a digit.

667656 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 (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2236 + ... + 2516.

It is an arithmetic number, because the mean of its divisors is an integer number (31725).

2⁶⁶⁷⁶⁵⁶ is an apocalyptic number.

667656 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 667656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1015200).

667656 is an abundant number, since it is smaller than the sum of its proper divisors (1362744).

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

667656 is a wasteful number, since it uses less digits than its factorization.

667656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307 (or 297 counting only the distinct ones).

The product of its digits is 45360, while the sum is 36.

The square root of 667656 is about 817.1021967906. The cubic root of 667656 is about 87.4012382288.

The spelling of 667656 in words is "six hundred sixty-seven thousand, six hundred fifty-six".