667987 has 2 divisors, whose sum is σ = 667988. Its totient is φ = 667986.

The previous prime is 667963. The next prime is 667991. The reversal of 667987 is 789766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 667987 - 2⁷ = 667859 is a prime.

It is an Ulam number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 667987.

It is not a weakly prime, because it can be changed into another prime (667487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333993 + 333994.

It is an arithmetic number, because the mean of its divisors is an integer number (333994).

2⁶⁶⁷⁹⁸⁷ is an apocalyptic number.

667987 is a deficient number, since it is larger than the sum of its proper divisors (1).

667987 is an equidigital number, since it uses as much as digits as its factorization.

667987 is an odious number, because the sum of its binary digits is odd.

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

The square root of 667987 is about 817.3047167367. The cubic root of 667987 is about 87.4156793134.

The spelling of 667987 in words is "six hundred sixty-seven thousand, nine hundred eighty-seven".