638059909 has 2 divisors, whose sum is σ = 638059910. Its totient is φ = 638059908.

The previous prime is 638059883. The next prime is 638059969. The reversal of 638059909 is 909950836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 338008225 + 300051684 = 18385^2 + 17322^2 .

It is a cyclic number.

It is not a de Polignac number, because 638059909 - 2⁷ = 638059781 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638059969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319029954 + 319029955.

It is an arithmetic number, because the mean of its divisors is an integer number (319029955).

Almost surely, 2^638059909 is an apocalyptic number.

It is an amenable number.

638059909 is a deficient number, since it is larger than the sum of its proper divisors (1).

638059909 is an equidigital number, since it uses as much as digits as its factorization.

638059909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 524880, while the sum is 49.

The square root of 638059909 is about 25259.8477628033. The cubic root of 638059909 is about 860.9022030926.

The spelling of 638059909 in words is "six hundred thirty-eight million, fifty-nine thousand, nine hundred nine".