81536000000 has 588 divisors, whose sum is σ = 255341145654. Its totient is φ = 25804800000.

The previous prime is 81535999969. The next prime is 81536000023. The reversal of 81536000000 is 63518.

It can be written as a sum of positive squares in 7 ways, for example, as 58742247424 + 22793752576 = 242368^2 + 150976^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81536000000.

It is an unprimeable number.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 6271999994 + ... + 6272000006.

Almost surely, 2^81536000000 is an apocalyptic number.

81536000000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81536000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127670572827).

81536000000 is an abundant number, since it is smaller than the sum of its proper divisors (173805145654).

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

81536000000 is an frugal number, since it uses more digits than its factorization.

81536000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 27 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

Adding to 81536000000 its reverse (63518), we get a palindrome (81536063518).

The spelling of 81536000000 in words is "eighty-one billion, five hundred thirty-six million", and thus it is an aban number.