81100217960 has 64 divisors (see below), whose sum is σ = 189153532800. Its totient is φ = 31257452800.

The previous prime is 81100217927. The next prime is 81100217963. The reversal of 81100217960 is 6971200118.

It is a Cunningham number, because it is equal to 284781²-1.

It is a self number, because there is not a number n which added to its sum of digits gives 81100217960.

It is not an unprimeable number, because it can be changed into a prime (81100217963) 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 15 ways as a sum of consecutive naturals, for example, 498365 + ... + 640755.

It is an arithmetic number, because the mean of its divisors is an integer number (2955523950).

Almost surely, 2^81100217960 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81100217960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94576766400).

81100217960 is an abundant number, since it is smaller than the sum of its proper divisors (108053314840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81100217960 is a wasteful number, since it uses less digits than its factorization.

81100217960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142922 (or 142918 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 35.

The spelling of 81100217960 in words is "eighty-one billion, one hundred million, two hundred seventeen thousand, nine hundred sixty".