309608 has 24 divisors (see below), whose sum is σ = 631350. Its totient is φ = 142272.

The previous prime is 309599. The next prime is 309623. The reversal of 309608 is 806903.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 232324 + 77284 = 482^2 + 278^2 .

It is a super-2 number, since 2×309608² = 191714227328, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is an unprimeable number.

309608 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 in 5 ways as a sum of consecutive naturals, for example, 1238 + ... + 1466.

2³⁰⁹⁶⁰⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 309608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (315675).

309608 is an abundant number, since it is smaller than the sum of its proper divisors (321742).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

309608 is a wasteful number, since it uses less digits than its factorization.

309608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261 (or 244 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 309608 is about 556.4242985349. The cubic root of 309608 is about 67.6504554283.

The spelling of 309608 in words is "three hundred nine thousand, six hundred eight".