137809 has 4 divisors (see below), whose sum is σ = 157504. Its totient is φ = 118116.

The previous prime is 137803. The next prime is 137827. The reversal of 137809 is 908731.

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 not a de Polignac number, because 137809 - 2⁵ = 137777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (137803) 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, 9837 + ... + 9850.

It is an arithmetic number, because the mean of its divisors is an integer number (39376).

2¹³⁷⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

137809 is a deficient number, since it is larger than the sum of its proper divisors (19695).

137809 is an equidigital number, since it uses as much as digits as its factorization.

137809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19694.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 137809 is about 371.2263460478. The cubic root of 137809 is about 51.6526404289.

It can be divided in two parts, 137 and 809, that added together give a triangular number (946 = T₄₃).

The spelling of 137809 in words is "one hundred thirty-seven thousand, eight hundred nine".