81817107556 has 24 divisors (see below), whose sum is σ = 144233913600. Its totient is φ = 40608374400.

The previous prime is 81817107551. The next prime is 81817107571. The reversal of 81817107556 is 65570171818.

It is not an unprimeable number, because it can be changed into a prime (81817107551) 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 in 7 ways as a sum of consecutive naturals, for example, 223836 + ... + 462316.

It is an arithmetic number, because the mean of its divisors is an integer number (6009746400).

Almost surely, 2^81817107556 is an apocalyptic number.

It is an amenable number.

81817107556 is a deficient number, since it is larger than the sum of its proper divisors (62416806044).

81817107556 is a wasteful number, since it uses less digits than its factorization.

81817107556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239115 (or 239113 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 49.

The spelling of 81817107556 in words is "eighty-one billion, eight hundred seventeen million, one hundred seven thousand, five hundred fifty-six".