309138946 has 4 divisors (see below), whose sum is σ = 463708422. Its totient is φ = 154569472.

The previous prime is 309138941. The next prime is 309138953. The reversal of 309138946 is 649831903.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 242144721 + 66994225 = 15561^2 + 8185^2 .

It is not an unprimeable number, because it can be changed into a prime (309138941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77284735 + ... + 77284738.

Almost surely, 2^309138946 is an apocalyptic number.

309138946 is a deficient number, since it is larger than the sum of its proper divisors (154569476).

309138946 is a wasteful number, since it uses less digits than its factorization.

309138946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154569475.

The product of its (nonzero) digits is 139968, while the sum is 43.

The square root of 309138946 is about 17582.3475679444. The cubic root of 309138946 is about 676.1627483573.

The spelling of 309138946 in words is "three hundred nine million, one hundred thirty-eight thousand, nine hundred forty-six".