81720682444325 has 12 divisors (see below), whose sum is σ = 101396940250788. Its totient is φ = 65335711104000.

The previous prime is 81720682444267. The next prime is 81720682444327. The reversal of 81720682444325 is 52344428602718.

It can be written as a sum of positive squares in 6 ways, for example, as 4653054524836 + 77067627919489 = 2157094^2 + 8778817^2 .

It is a de Polignac number, because none of the positive numbers 2^k-81720682444325 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81720682444327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1020830462 + ... + 1020910511.

It is an arithmetic number, because the mean of its divisors is an integer number (8449745020899).

Almost surely, 2^{81720682444325} is an apocalyptic number.

It is an amenable number.

81720682444325 is a deficient number, since it is larger than the sum of its proper divisors (19676257806463).

81720682444325 is a wasteful number, since it uses less digits than its factorization.

81720682444325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2041742584 (or 2041742579 counting only the distinct ones).

The product of its (nonzero) digits is 20643840, while the sum is 56.

The spelling of 81720682444325 in words is "eighty-one trillion, seven hundred twenty billion, six hundred eighty-two million, four hundred forty-four thousand, three hundred twenty-five".