77309 has 4 divisors (see below), whose sum is σ = 78204. Its totient is φ = 76416.

The previous prime is 77291. The next prime is 77317. The reversal of 77309 is 90377.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90377 = 7 ⋅12911.

It can be written as a sum of positive squares in 2 ways, for example, as 36100 + 41209 = 190^2 + 203^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77309 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77339) 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, 302 + ... + 495.

It is an arithmetic number, because the mean of its divisors is an integer number (19551).

2⁷⁷³⁰⁹ is an apocalyptic number.

It is an amenable number.

77309 is a deficient number, since it is larger than the sum of its proper divisors (895).

77309 is an equidigital number, since it uses as much as digits as its factorization.

77309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 894.

The product of its (nonzero) digits is 1323, while the sum is 26.

The square root of 77309 is about 278.0449603931. The cubic root of 77309 is about 42.6000411441.

The spelling of 77309 in words is "seventy-seven thousand, three hundred nine".