309768138 has 28 divisors (see below), whose sum is σ = 696662898. Its totient is φ = 103255560.

The previous prime is 309768131. The next prime is 309768247. The reversal of 309768138 is 831867903.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 307055529 + 2712609 = 17523^2 + 1647^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 309768093 and 309768102.

It is not an unprimeable number, because it can be changed into a prime (309768131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 104773 + ... + 107688.

Almost surely, 2^309768138 is an apocalyptic number.

309768138 is an abundant number, since it is smaller than the sum of its proper divisors (386894760).

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

309768138 is an equidigital number, since it uses as much as digits as its factorization.

309768138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212481 (or 212466 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 309768138 is about 17600.2311916634. The cubic root of 309768138 is about 676.6211699318.

The spelling of 309768138 in words is "three hundred nine million, seven hundred sixty-eight thousand, one hundred thirty-eight".