100809509 has 2 divisors, whose sum is σ = 100809510. Its totient is φ = 100809508.

The previous prime is 100809503. The next prime is 100809517. The reversal of 100809509 is 905908001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80604484 + 20205025 = 8978^2 + 4495^2 .

It is an emirp because it is prime and its reverse (905908001) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 100809509 - 2⁴ = 100809493 is a prime.

It is a Chen prime.

It is equal to p_5805248 and since 100809509 and 5805248 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100809503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50404754 + 50404755.

It is an arithmetic number, because the mean of its divisors is an integer number (50404755).

Almost surely, 2^100809509 is an apocalyptic number.

It is an amenable number.

100809509 is a deficient number, since it is larger than the sum of its proper divisors (1).

100809509 is an equidigital number, since it uses as much as digits as its factorization.

100809509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 32.

The square root of 100809509 is about 10040.3938667763. The cubic root of 100809509 is about 465.4079881732.

The spelling of 100809509 in words is "one hundred million, eight hundred nine thousand, five hundred nine".