309988 has 12 divisors (see below), whose sum is σ = 620032. Its totient is φ = 132840.

The previous prime is 309977. The next prime is 309989. The reversal of 309988 is 889903.

309988 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (309989) 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, 5508 + ... + 5563.

2³⁰⁹⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

309988 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

309988 is a wasteful number, since it uses less digits than its factorization.

309988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11082 (or 11080 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 309988 is about 556.7656598606. The cubic root of 309988 is about 67.6781212325.

The spelling of 309988 in words is "three hundred nine thousand, nine hundred eighty-eight".