309247 has 4 divisors (see below), whose sum is σ = 327456. Its totient is φ = 291040.

The previous prime is 309241. The next prime is 309251. The reversal of 309247 is 742903.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 742903 = 7 ⋅106129.

It is a de Polignac number, because none of the positive numbers 2^k-309247 is a prime.

It is a Duffinian number.

309247 is a lucky number.

It is a plaindrome in base 8.

It is a zygodrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (309241) 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, 9079 + ... + 9112.

It is an arithmetic number, because the mean of its divisors is an integer number (81864).

2³⁰⁹²⁴⁷ is an apocalyptic number.

309247 is a deficient number, since it is larger than the sum of its proper divisors (18209).

309247 is a wasteful number, since it uses less digits than its factorization.

309247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18208.

The product of its (nonzero) digits is 1512, while the sum is 25.

The square root of 309247 is about 556.0998111850. The cubic root of 309247 is about 67.6241519386.

The spelling of 309247 in words is "three hundred nine thousand, two hundred forty-seven".