72804209 has 2 divisors, whose sum is σ = 72804210. Its totient is φ = 72804208.

The previous prime is 72804163. The next prime is 72804241. The reversal of 72804209 is 90240827.

It is an a-pointer prime, because the next prime (72804241) can be obtained adding 72804209 to its sum of digits (32).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39337984 + 33466225 = 6272^2 + 5785^2 .

It is an emirp because it is prime and its reverse (90240827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72804209 - 2¹² = 72800113 is a prime.

It is a Chen prime.

It is equal to p_4273187 and since 72804209 and 4273187 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (72804299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36402104 + 36402105.

It is an arithmetic number, because the mean of its divisors is an integer number (36402105).

Almost surely, 2^72804209 is an apocalyptic number.

It is an amenable number.

72804209 is a deficient number, since it is larger than the sum of its proper divisors (1).

72804209 is an equidigital number, since it uses as much as digits as its factorization.

72804209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 72804209 is about 8532.5382507200. The cubic root of 72804209 is about 417.5599426286.

The spelling of 72804209 in words is "seventy-two million, eight hundred four thousand, two hundred nine".