667968 has 84 divisors (see below), whose sum is σ = 2084832. Its totient is φ = 188160.

The previous prime is 667963. The next prime is 667987. The reversal of 667968 is 869766.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (84).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667963) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9373 + ... + 9443.

2⁶⁶⁷⁹⁶⁸ 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 667968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1042416).

667968 is an abundant number, since it is smaller than the sum of its proper divisors (1416864).

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

667968 is a wasteful number, since it uses less digits than its factorization.

667968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100 (or 83 counting only the distinct ones).

The product of its digits is 108864, while the sum is 42.

The square root of 667968 is about 817.2930930823. The cubic root of 667968 is about 87.4148504981.

The spelling of 667968 in words is "six hundred sixty-seven thousand, nine hundred sixty-eight".