139281709 has 4 divisors (see below), whose sum is σ = 159179104. Its totient is φ = 119384316.

The previous prime is 139281691. The next prime is 139281743. The reversal of 139281709 is 907182931.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139281709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139261709) 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, 9948687 + ... + 9948700.

It is an arithmetic number, because the mean of its divisors is an integer number (39794776).

Almost surely, 2^139281709 is an apocalyptic number.

It is an amenable number.

139281709 is a deficient number, since it is larger than the sum of its proper divisors (19897395).

139281709 is an equidigital number, since it uses as much as digits as its factorization.

139281709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19897394.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 139281709 is about 11801.7671981784. The cubic root of 139281709 is about 518.3598581239.

The spelling of 139281709 in words is "one hundred thirty-nine million, two hundred eighty-one thousand, seven hundred nine".