309705 has 16 divisors (see below), whose sum is σ = 540864. Its totient is φ = 150080.

The previous prime is 309677. The next prime is 309707. The reversal of 309705 is 507903.

It is not a de Polignac number, because 309705 - 2⁷ = 309577 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (309707) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 774 + ... + 1103.

It is an arithmetic number, because the mean of its divisors is an integer number (33804).

2³⁰⁹⁷⁰⁵ is an apocalyptic number.

It is an amenable number.

309705 is a deficient number, since it is larger than the sum of its proper divisors (231159).

309705 is a wasteful number, since it uses less digits than its factorization.

309705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1896.

The product of its (nonzero) digits is 945, while the sum is 24.

The square root of 309705 is about 556.5114554077. The cubic root of 309705 is about 67.6575196395.

The spelling of 309705 in words is "three hundred nine thousand, seven hundred five".