667426 has 4 divisors (see below), whose sum is σ = 1001142. Its totient is φ = 333712.

The previous prime is 667423. The next prime is 667427. The reversal of 667426 is 624766.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 624766 = 2 ⋅312383.

It can be written as a sum of positive squares in only one way, i.e., 366025 + 301401 = 605^2 + 549^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166855 + ... + 166858.

2⁶⁶⁷⁴²⁶ is an apocalyptic number.

667426 is a deficient number, since it is larger than the sum of its proper divisors (333716).

667426 is a wasteful number, since it uses less digits than its factorization.

667426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333715.

The product of its digits is 12096, while the sum is 31.

The square root of 667426 is about 816.9614433986. The cubic root of 667426 is about 87.3912008275.

The spelling of 667426 in words is "six hundred sixty-seven thousand, four hundred twenty-six".