139986 has 48 divisors (see below), whose sum is σ = 381888. Its totient is φ = 36000.

The previous prime is 139981. The next prime is 139987. The reversal of 139986 is 689931.

It is a self number, because there is not a number n which added to its sum of digits gives 139986.

It is not an unprimeable number, because it can be changed into a prime (139981) by changing a digit.

139986 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1336 + ... + 1436.

It is an arithmetic number, because the mean of its divisors is an integer number (7956).

139986 is a Friedman number, since it can be written as (9+9)*(6^(8-3)+1), using all its digits and the basic arithmetic operations.

2¹³⁹⁹⁸⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 139986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (190944).

139986 is an abundant number, since it is smaller than the sum of its proper divisors (241902).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

139986 is a wasteful number, since it uses less digits than its factorization.

139986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127 (or 124 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 139986 is about 374.1470299227. The cubic root of 139986 is about 51.9232101294.

Subtracting 139986 from its reverse (689931), we obtain a palindrome (549945).

It can be divided in two parts, 1399 and 86, that added together give a triangular number (1485 = T₅₄).

The spelling of 139986 in words is "one hundred thirty-nine thousand, nine hundred eighty-six".