649131209 has 2 divisors, whose sum is σ = 649131210. Its totient is φ = 649131208.

The previous prime is 649131193. The next prime is 649131211. The reversal of 649131209 is 902131946.

649131209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 645414025 + 3717184 = 25405^2 + 1928^2 .

It is a cyclic number.

It is not a de Polignac number, because 649131209 - 2⁴ = 649131193 is a prime.

Together with 649131211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (649131299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324565604 + 324565605.

It is an arithmetic number, because the mean of its divisors is an integer number (324565605).

Almost surely, 2^649131209 is an apocalyptic number.

It is an amenable number.

649131209 is a deficient number, since it is larger than the sum of its proper divisors (1).

649131209 is an equidigital number, since it uses as much as digits as its factorization.

649131209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 649131209 is about 25478.0534774539. The cubic root of 649131209 is about 865.8529944240.

The spelling of 649131209 in words is "six hundred forty-nine million, one hundred thirty-one thousand, two hundred nine".