81181612624 has 80 divisors (see below), whose sum is σ = 183058819200. Its totient is φ = 34155136512.

The previous prime is 81181612621. The next prime is 81181612627. The reversal of 81181612624 is 42621618118.

It is an interprime number because it is at equal distance from previous prime (81181612621) and next prime (81181612627).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81181612621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4994142 + ... + 5010370.

It is an arithmetic number, because the mean of its divisors is an integer number (2288235240).

Almost surely, 2^81181612624 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 81181612624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91529409600).

81181612624 is an abundant number, since it is smaller than the sum of its proper divisors (101877206576).

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

81181612624 is a wasteful number, since it uses less digits than its factorization.

81181612624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17060 (or 17054 counting only the distinct ones).

The product of its digits is 36864, while the sum is 40.

The spelling of 81181612624 in words is "eighty-one billion, one hundred eighty-one million, six hundred twelve thousand, six hundred twenty-four".