81517604801 has 4 divisors (see below), whose sum is σ = 85061848512. Its totient is φ = 77973361092.

The previous prime is 81517604713. The next prime is 81517604869. The reversal of 81517604801 is 10840671518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81517604801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81517604101) 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 3 ways as a sum of consecutive naturals, for example, 1772121821 + ... + 1772121866.

It is an arithmetic number, because the mean of its divisors is an integer number (21265462128).

Almost surely, 2^81517604801 is an apocalyptic number.

It is an amenable number.

81517604801 is a deficient number, since it is larger than the sum of its proper divisors (3544243711).

81517604801 is a wasteful number, since it uses less digits than its factorization.

81517604801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3544243710.

The product of its (nonzero) digits is 53760, while the sum is 41.

The spelling of 81517604801 in words is "eighty-one billion, five hundred seventeen million, six hundred four thousand, eight hundred one".