72718487521 has 2 divisors, whose sum is σ = 72718487522. Its totient is φ = 72718487520.

The previous prime is 72718487503. The next prime is 72718487549. The reversal of 72718487521 is 12578481727.

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., 60720352225 + 11998135296 = 246415^2 + 109536^2 .

It is a cyclic number.

It is not a de Polignac number, because 72718487521 - 2⁵ = 72718487489 is a prime.

It is a super-3 number, since 3×72718487521³ (a number of 34 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (72718437521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36359243760 + 36359243761.

It is an arithmetic number, because the mean of its divisors is an integer number (36359243761).

Almost surely, 2^72718487521 is an apocalyptic number.

It is an amenable number.

72718487521 is a deficient number, since it is larger than the sum of its proper divisors (1).

72718487521 is an equidigital number, since it uses as much as digits as its factorization.

72718487521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1756160, while the sum is 52.

The spelling of 72718487521 in words is "seventy-two billion, seven hundred eighteen million, four hundred eighty-seven thousand, five hundred twenty-one".