309649609 has 2 divisors, whose sum is σ = 309649610. Its totient is φ = 309649608.

The previous prime is 309649597. The next prime is 309649619. The reversal of 309649609 is 906946903.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 293368384 + 16281225 = 17128^2 + 4035^2 .

It is an emirp because it is prime and its reverse (906946903) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 309649609 - 2²⁷ = 175431881 is a prime.

It is not a weakly prime, because it can be changed into another prime (309649619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 154824804 + 154824805.

It is an arithmetic number, because the mean of its divisors is an integer number (154824805).

Almost surely, 2^309649609 is an apocalyptic number.

It is an amenable number.

309649609 is a deficient number, since it is larger than the sum of its proper divisors (1).

309649609 is an equidigital number, since it uses as much as digits as its factorization.

309649609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 314928, while the sum is 46.

The square root of 309649609 is about 17596.8636125873. The cubic root of 309649609 is about 676.5348586428.

The spelling of 309649609 in words is "three hundred nine million, six hundred forty-nine thousand, six hundred nine".