207138809 has 2 divisors, whose sum is σ = 207138810. Its totient is φ = 207138808.

The previous prime is 207138803. The next prime is 207138853. The reversal of 207138809 is 908831702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 167133184 + 40005625 = 12928^2 + 6325^2 .

It is a cyclic number.

It is not a de Polignac number, because 207138809 - 2²⁰ = 206090233 is a prime.

It is not a weakly prime, because it can be changed into another prime (207138803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103569404 + 103569405.

It is an arithmetic number, because the mean of its divisors is an integer number (103569405).

Almost surely, 2^207138809 is an apocalyptic number.

It is an amenable number.

207138809 is a deficient number, since it is larger than the sum of its proper divisors (1).

207138809 is an equidigital number, since it uses as much as digits as its factorization.

207138809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 207138809 is about 14392.3177077217. The cubic root of 207138809 is about 591.6803662062.

The spelling of 207138809 in words is "two hundred seven million, one hundred thirty-eight thousand, eight hundred nine".