81733857454368 has 432 divisors, whose sum is σ = 291684752344440. Its totient is φ = 21564153741312.

The previous prime is 81733857454343. The next prime is 81733857454369. The reversal of 81733857454368 is 86345475833718.

81733857454368 is a `hidden beast` number, since 8 + 1 + 7 + 3 + 3 + 8 + 5 + 74 + 543 + 6 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 77885778885264 + 3848078569104 = 8825292^2 + 1961652^2 .

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 81733857454296 and 81733857454305.

It is not an unprimeable number, because it can be changed into a prime (81733857454369) 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 71 ways as a sum of consecutive naturals, for example, 9500818 + ... + 15929006.

Almost surely, 2^{81733857454368} 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 81733857454368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145842376172220).

81733857454368 is an abundant number, since it is smaller than the sum of its proper divisors (209950894890072).

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

81733857454368 is a wasteful number, since it uses less digits than its factorization.

81733857454368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6428289 (or 6428271 counting only the distinct ones).

The product of its digits is 1625702400, while the sum is 72.

The spelling of 81733857454368 in words is "eighty-one trillion, seven hundred thirty-three billion, eight hundred fifty-seven million, four hundred fifty-four thousand, three hundred sixty-eight".