667989 has 24 divisors (see below), whose sum is σ = 1153152. Its totient is φ = 364320.

The previous prime is 667987. The next prime is 667991. The reversal of 667989 is 989766.

It is an interprime number because it is at equal distance from previous prime (667987) and next prime (667991).

It is not a de Polignac number, because 667989 - 2¹ = 667987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667987) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1219 + ... + 1679.

It is an arithmetic number, because the mean of its divisors is an integer number (48048).

2⁶⁶⁷⁹⁸⁹ is an apocalyptic number.

667989 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

It is an amenable number.

667989 is a deficient number, since it is larger than the sum of its proper divisors (485163).

667989 is a wasteful number, since it uses less digits than its factorization.

667989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 497 (or 494 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 667989 is about 817.3059402696. The cubic root of 667989 is about 87.4157665562.

The spelling of 667989 in words is "six hundred sixty-seven thousand, nine hundred eighty-nine".