640466009 has 2 divisors, whose sum is σ = 640466010. Its totient is φ = 640466008.

The previous prime is 640465999. The next prime is 640466017. The reversal of 640466009 is 900664046.

640466009 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., 379158784 + 261307225 = 19472^2 + 16165^2 .

It is a cyclic number.

It is not a de Polignac number, because 640466009 - 2⁴ = 640465993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640466009.

It is not a weakly prime, because it can be changed into another prime (640466089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320233004 + 320233005.

It is an arithmetic number, because the mean of its divisors is an integer number (320233005).

Almost surely, 2^640466009 is an apocalyptic number.

It is an amenable number.

640466009 is a deficient number, since it is larger than the sum of its proper divisors (1).

640466009 is an equidigital number, since it uses as much as digits as its factorization.

640466009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 640466009 is about 25307.4299169236. The cubic root of 640466009 is about 861.9829890072.

The spelling of 640466009 in words is "six hundred forty million, four hundred sixty-six thousand, nine".