309742 has 4 divisors (see below), whose sum is σ = 464616. Its totient is φ = 154870.

The previous prime is 309737. The next prime is 309769. The reversal of 309742 is 247903.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 247903 = 157 ⋅1579.

It is a congruent number.

It is an unprimeable number.

309742 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77434 + ... + 77437.

It is an arithmetic number, because the mean of its divisors is an integer number (116154).

2³⁰⁹⁷⁴² is an apocalyptic number.

309742 is a deficient number, since it is larger than the sum of its proper divisors (154874).

309742 is a wasteful number, since it uses less digits than its factorization.

309742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154873.

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

The square root of 309742 is about 556.5446972167. The cubic root of 309742 is about 67.6602138470.

It can be divided in two parts, 30974 and 2, that added together give a square (30976 = 176²).

The spelling of 309742 in words is "three hundred nine thousand, seven hundred forty-two".