667538 has 4 divisors (see below), whose sum is σ = 1001310. Its totient is φ = 333768.

The previous prime is 667531. The next prime is 667547. The reversal of 667538 is 835766.

It is a happy number.

667538 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 835766 = 2 ⋅417883.

It can be written as a sum of positive squares in only one way, i.e., 667489 + 49 = 817^2 + 7^2 .

It is a junction number, because it is equal to n+sod(n) for n = 667498 and 667507.

It is not an unprimeable number, because it can be changed into a prime (667531) by changing a digit.

667538 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 as a sum of consecutive naturals, namely, 166883 + ... + 166886.

2⁶⁶⁷⁵³⁸ is an apocalyptic number.

667538 is a deficient number, since it is larger than the sum of its proper divisors (333772).

667538 is a wasteful number, since it uses less digits than its factorization.

667538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333771.

The product of its digits is 30240, while the sum is 35.

The square root of 667538 is about 817.0299872098. The cubic root of 667538 is about 87.3960888935.

The spelling of 667538 in words is "six hundred sixty-seven thousand, five hundred thirty-eight".