667720 has 16 divisors (see below), whose sum is σ = 1502460. Its totient is φ = 267072.

The previous prime is 667699. The next prime is 667727. The reversal of 667720 is 27766.

It can be written as a sum of positive squares in 2 ways, for example, as 599076 + 68644 = 774^2 + 262^2 .

It is not an unprimeable number, because it can be changed into a prime (667727) by changing a digit.

667720 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8307 + ... + 8386.

2⁶⁶⁷⁷²⁰ is an apocalyptic number.

It is an amenable number.

667720 is an abundant number, since it is smaller than the sum of its proper divisors (834740).

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

667720 is a wasteful number, since it uses less digits than its factorization.

667720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16704 (or 16700 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 28.

The square root of 667720 is about 817.1413586400. The cubic root of 667720 is about 87.4040308348.

The spelling of 667720 in words is "six hundred sixty-seven thousand, seven hundred twenty".