667789 has 4 divisors (see below), whose sum is σ = 677824. Its totient is φ = 657756.

The previous prime is 667781. The next prime is 667801. The reversal of 667789 is 987766.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 667789 - 2³ = 667781 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4917 + ... + 5050.

It is an arithmetic number, because the mean of its divisors is an integer number (169456).

2⁶⁶⁷⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

667789 is a deficient number, since it is larger than the sum of its proper divisors (10035).

667789 is an equidigital number, since it uses as much as digits as its factorization.

667789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10034.

The product of its digits is 127008, while the sum is 43.

The square root of 667789 is about 817.1835779065. The cubic root of 667789 is about 87.4070414133.

The spelling of 667789 in words is "six hundred sixty-seven thousand, seven hundred eighty-nine".