139989 has 4 divisors (see below), whose sum is σ = 186656. Its totient is φ = 93324.

The previous prime is 139987. The next prime is 139991. The reversal of 139989 is 989931.

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, and also an emirpimes, since its reverse is a distinct semiprime: 989931 = 3 ⋅329977.

It is an interprime number because it is at equal distance from previous prime (139987) and next prime (139991).

It is not a de Polignac number, because 139989 - 2¹ = 139987 is a prime.

It is a D-number.

It is a Duffinian number.

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 139989.

It is not an unprimeable number, because it can be changed into a prime (139981) 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, 23329 + ... + 23334.

It is an arithmetic number, because the mean of its divisors is an integer number (46664).

2¹³⁹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

139989 is a deficient number, since it is larger than the sum of its proper divisors (46667).

139989 is an equidigital number, since it uses as much as digits as its factorization.

139989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46666.

The product of its digits is 17496, while the sum is 39.

The square root of 139989 is about 374.1510390203. The cubic root of 139989 is about 51.9235810440.

It can be divided in two parts, 139 and 989, that added together give a triangular number (1128 = T₄₇).

The spelling of 139989 in words is "one hundred thirty-nine thousand, nine hundred eighty-nine".