649140809 has 2 divisors, whose sum is σ = 649140810. Its totient is φ = 649140808.

The previous prime is 649140803. The next prime is 649140851. The reversal of 649140809 is 908041946.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 397125184 + 252015625 = 19928^2 + 15875^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649140809 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (649140803) 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, 324570404 + 324570405.

It is an arithmetic number, because the mean of its divisors is an integer number (324570405).

Almost surely, 2^649140809 is an apocalyptic number.

It is an amenable number.

649140809 is a deficient number, since it is larger than the sum of its proper divisors (1).

649140809 is an equidigital number, since it uses as much as digits as its factorization.

649140809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 649140809 is about 25478.2418741953. The cubic root of 649140809 is about 865.8572627690.

The spelling of 649140809 in words is "six hundred forty-nine million, one hundred forty thousand, eight hundred nine".