649708309 has 2 divisors, whose sum is σ = 649708310. Its totient is φ = 649708308.

The previous prime is 649708237. The next prime is 649708321. The reversal of 649708309 is 903807946.

649708309 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., 427042225 + 222666084 = 20665^2 + 14922^2 .

It is a cyclic number.

It is not a de Polignac number, because 649708309 - 2⁹ = 649707797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649708349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324854154 + 324854155.

It is an arithmetic number, because the mean of its divisors is an integer number (324854155).

Almost surely, 2^649708309 is an apocalyptic number.

It is an amenable number.

649708309 is a deficient number, since it is larger than the sum of its proper divisors (1).

649708309 is an equidigital number, since it uses as much as digits as its factorization.

649708309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 326592, while the sum is 46.

The square root of 649708309 is about 25489.3763948826. The cubic root of 649708309 is about 866.1095094657.

The spelling of 649708309 in words is "six hundred forty-nine million, seven hundred eight thousand, three hundred nine".