138942 has 32 divisors (see below), whose sum is σ = 322560. Its totient is φ = 44280.

The previous prime is 138937. The next prime is 138959. The reversal of 138942 is 249831.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nialpdrome in base 11.

It is a congruent number.

It is an unprimeable number.

138942 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 (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1633 + ... + 1715.

It is an arithmetic number, because the mean of its divisors is an integer number (10080).

2¹³⁸⁹⁴² is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138942, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (161280).

138942 is an abundant number, since it is smaller than the sum of its proper divisors (183618).

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

138942 is a wasteful number, since it uses less digits than its factorization.

138942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 119 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 138942 is about 372.7492454721. The cubic root of 138942 is about 51.7938087342.

Subtracting 138942 from its reverse (249831), we obtain a square (110889 = 333²).

It can be divided in two parts, 1389 and 42, that added together give a triangular number (1431 = T₅₃).

The spelling of 138942 in words is "one hundred thirty-eight thousand, nine hundred forty-two".