81972360288 has 1296 divisors, whose sum is σ = 325317021120. Its totient is φ = 20175547392.

The previous prime is 81972360247. The next prime is 81972360311. The reversal of 81972360288 is 88206327918.

It is a happy number.

81972360288 is a `hidden beast` number, since 8 + 1 + 9 + 7 + 23 + 602 + 8 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (1296).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

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 215 ways as a sum of consecutive naturals, for example, 1223468031 + ... + 1223468097.

It is an arithmetic number, because the mean of its divisors is an integer number (251016220).

Almost surely, 2^81972360288 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 81972360288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162658510560).

81972360288 is an abundant number, since it is smaller than the sum of its proper divisors (243344660832).

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

81972360288 is a wasteful number, since it uses less digits than its factorization.

81972360288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 54.

The spelling of 81972360288 in words is "eighty-one billion, nine hundred seventy-two million, three hundred sixty thousand, two hundred eighty-eight".