81845644654818 has 96 divisors (see below), whose sum is σ = 193888591408512. Its totient is φ = 24745918003200.

The previous prime is 81845644654817. The next prime is 81845644654883.

81845644654818 is a `hidden beast` number, since 8 + 1 + 8 + 4 + 5 + 64 + 4 + 6 + 548 + 18 = 666.

81845644654818 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×81845644654818² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81845644654817) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1454669355 + ... + 1454725617.

It is an arithmetic number, because the mean of its divisors is an integer number (2019672827172).

Almost surely, 2^{81845644654818} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81845644654818, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96944295704256).

81845644654818 is an abundant number, since it is smaller than the sum of its proper divisors (112042946753694).

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

81845644654818 is a wasteful number, since it uses less digits than its factorization.

81845644654818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72680 (or 72677 counting only the distinct ones).

The product of its digits is 943718400, while the sum is 72.

The spelling of 81845644654818 in words is "eighty-one trillion, eight hundred forty-five billion, six hundred forty-four million, six hundred fifty-four thousand, eight hundred eighteen".