81186755449536 has 336 divisors, whose sum is σ = 254449042219008. Its totient is φ = 24545258496000.

The previous prime is 81186755449477. The next prime is 81186755449543. The reversal of 81186755449536 is 63594455768118.

81186755449536 is a `hidden beast` number, since 8 + 1 + 1 + 8 + 6 + 75 + 544 + 9 + 5 + 3 + 6 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5301811416 + ... + 5301826728.

It is an arithmetic number, because the mean of its divisors is an integer number (757288816128).

Almost surely, 2^{81186755449536} 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 81186755449536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127224521109504).

81186755449536 is an abundant number, since it is smaller than the sum of its proper divisors (173262286769472).

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

81186755449536 is a wasteful number, since it uses less digits than its factorization.

81186755449536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17220 (or 17207 counting only the distinct ones).

The product of its digits is 870912000, while the sum is 72.

The spelling of 81186755449536 in words is "eighty-one trillion, one hundred eighty-six billion, seven hundred fifty-five million, four hundred forty-nine thousand, five hundred thirty-six".