139509 has 8 divisors (see below), whose sum is σ = 206720. Its totient is φ = 92988.

The previous prime is 139501. The next prime is 139511. The reversal of 139509 is 905931.

It is not a de Polignac number, because 139509 - 2³ = 139501 is a prime.

It is a super-2 number, since 2×139509² = 38925522162, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 5167 = 139509 / (1 + 3 + 9 + 5 + 0 + 9).

It is a Duffinian number.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2557 + ... + 2610.

It is an arithmetic number, because the mean of its divisors is an integer number (25840).

2¹³⁹⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

139509 is a deficient number, since it is larger than the sum of its proper divisors (67211).

139509 is an equidigital number, since it uses as much as digits as its factorization.

139509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5176 (or 5170 counting only the distinct ones).

The product of its (nonzero) digits is 1215, while the sum is 27.

The square root of 139509 is about 373.5090360353. The cubic root of 139509 is about 51.8641671869.

The spelling of 139509 in words is "one hundred thirty-nine thousand, five hundred nine".