It is a happy number.
137999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a weak prime.
It is a cyclic number.
It is a Sophie Germain prime.
It is a Chen prime.
It is a plaindrome in base 10.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 137999.
2137999 is an apocalyptic number.
137999 is an equidigital number, since it uses as much as digits as its factorization.
137999 is an odious number, because the sum of its binary digits is odd.
The square root of 137999 is about 371.4821664629. The cubic root of 137999 is about 51.6763677009.
The spelling of 137999 in words is "one hundred thirty-seven thousand, nine hundred ninety-nine".