309912 has 32 divisors (see below), whose sum is σ = 798000. Its totient is φ = 100224.

The previous prime is 309899. The next prime is 309929. The reversal of 309912 is 219903.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 309912.

It is an unprimeable number.

309912 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 7 ways as a sum of consecutive naturals, for example, 714 + ... + 1062.

2³⁰⁹⁹¹² 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 309912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (399000).

309912 is an abundant number, since it is smaller than the sum of its proper divisors (488088).

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

309912 is a wasteful number, since it uses less digits than its factorization.

309912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395 (or 391 counting only the distinct ones).

The product of its (nonzero) digits is 486, while the sum is 24.

The square root of 309912 is about 556.6974043410. The cubic root of 309912 is about 67.6725898811.

Subtracting from 309912 its reverse (219903), we obtain a palindrome (90009).

It can be divided in two parts, 309 and 912, that added together give a palindrome (1221).

The spelling of 309912 in words is "three hundred nine thousand, nine hundred twelve".