72645509 has 2 divisors, whose sum is σ = 72645510. Its totient is φ = 72645508.

The previous prime is 72645499. The next prime is 72645589. The reversal of 72645509 is 90554627.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72624484 + 21025 = 8522^2 + 145^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72645509 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72645589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36322754 + 36322755.

It is an arithmetic number, because the mean of its divisors is an integer number (36322755).

Almost surely, 2^72645509 is an apocalyptic number.

It is an amenable number.

72645509 is a deficient number, since it is larger than the sum of its proper divisors (1).

72645509 is an equidigital number, since it uses as much as digits as its factorization.

72645509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 75600, while the sum is 38.

The square root of 72645509 is about 8523.2334826637. The cubic root of 72645509 is about 417.2563202050.

The spelling of 72645509 in words is "seventy-two million, six hundred forty-five thousand, five hundred nine".