127989 has 6 divisors (see below), whose sum is σ = 184886. Its totient is φ = 85320.

The previous prime is 127979. The next prime is 127997. The reversal of 127989 is 989721.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 116964 + 11025 = 342^2 + 105^2 .

It is not a de Polignac number, because 127989 - 2⁴ = 127973 is a prime.

It is a Duffinian number.

127989 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (127979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7102 + ... + 7119.

2¹²⁷⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

127989 is a deficient number, since it is larger than the sum of its proper divisors (56897).

127989 is a wasteful number, since it uses less digits than its factorization.

127989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14227 (or 14224 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 127989 is about 357.7555031023. The cubic root of 127989 is about 50.3953982949.

It can be divided in two parts, 12 and 7989, that added together give a triangular number (8001 = T₁₂₆).

The spelling of 127989 in words is "one hundred twenty-seven thousand, nine hundred eighty-nine".