667644 has 48 divisors (see below), whose sum is σ = 1693440. Its totient is φ = 204160.

The previous prime is 667643. The next prime is 667649. The reversal of 667644 is 446766.

Its product of digits (24192) is a multiple of the sum of its prime divisors (128).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 667644.

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

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11287 + ... + 11345.

It is an arithmetic number, because the mean of its divisors is an integer number (35280).

2⁶⁶⁷⁶⁴⁴ 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 667644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (846720).

667644 is an abundant number, since it is smaller than the sum of its proper divisors (1025796).

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

667644 is a wasteful number, since it uses less digits than its factorization.

667644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130 (or 128 counting only the distinct ones).

The product of its digits is 24192, while the sum is 33.

The square root of 667644 is about 817.0948537349. The cubic root of 667644 is about 87.4007145953.

The spelling of 667644 in words is "six hundred sixty-seven thousand, six hundred forty-four".