136723409 has 4 divisors (see below), whose sum is σ = 136750260. Its totient is φ = 136696560.

The previous prime is 136723337. The next prime is 136723417. The reversal of 136723409 is 904327631.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 904327631 = 17 ⋅53195743.

It can be written as a sum of positive squares in 2 ways, for example, as 33640000 + 103083409 = 5800^2 + 10153^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-136723409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (136723439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3182 + ... + 16839.

It is an arithmetic number, because the mean of its divisors is an integer number (34187565).

Almost surely, 2^136723409 is an apocalyptic number.

It is an amenable number.

136723409 is a deficient number, since it is larger than the sum of its proper divisors (26851).

136723409 is an equidigital number, since it uses as much as digits as its factorization.

136723409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26850.

The product of its (nonzero) digits is 27216, while the sum is 35.

The square root of 136723409 is about 11692.8785591915. The cubic root of 136723409 is about 515.1665141637.

The spelling of 136723409 in words is "one hundred thirty-six million, seven hundred twenty-three thousand, four hundred nine".