139805 has 4 divisors (see below), whose sum is σ = 167772. Its totient is φ = 111840.

The previous prime is 139801. The next prime is 139813. The reversal of 139805 is 508931.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 41209 + 98596 = 203^2 + 314^2 .

It is not a de Polignac number, because 139805 - 2² = 139801 is a prime.

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 139805.

It is not an unprimeable number, because it can be changed into a prime (139801) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 13976 + ... + 13985.

It is an arithmetic number, because the mean of its divisors is an integer number (41943).

2¹³⁹⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

139805 is a deficient number, since it is larger than the sum of its proper divisors (27967).

139805 is an equidigital number, since it uses as much as digits as its factorization.

139805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27966.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 139805 is about 373.9050681657. The cubic root of 139805 is about 51.9008218085.

The spelling of 139805 in words is "one hundred thirty-nine thousand, eight hundred five".