72517520909 has 2 divisors, whose sum is σ = 72517520910. Its totient is φ = 72517520908.

The previous prime is 72517520899. The next prime is 72517520917. The reversal of 72517520909 is 90902571527.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72401355625 + 116165284 = 269075^2 + 10778^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72517520909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72517520969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36258760454 + 36258760455.

It is an arithmetic number, because the mean of its divisors is an integer number (36258760455).

Almost surely, 2^72517520909 is an apocalyptic number.

It is an amenable number.

72517520909 is a deficient number, since it is larger than the sum of its proper divisors (1).

72517520909 is an equidigital number, since it uses as much as digits as its factorization.

72517520909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 396900, while the sum is 47.

The spelling of 72517520909 in words is "seventy-two billion, five hundred seventeen million, five hundred twenty thousand, nine hundred nine".