81538016000 has 288 divisors, whose sum is σ = 233921181312. Its totient is φ = 27741388800.

The previous prime is 81538015997. The next prime is 81538016023. The reversal of 81538016000 is 61083518.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30686672 + ... + 30689328.

It is an arithmetic number, because the mean of its divisors is an integer number (812226324).

Almost surely, 2^81538016000 is an apocalyptic number.

81538016000 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 81538016000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116960590656).

81538016000 is an abundant number, since it is smaller than the sum of its proper divisors (152383165312).

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

81538016000 is a wasteful number, since it uses less digits than its factorization.

81538016000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2832 (or 2808 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 32.

Adding to 81538016000 its reverse (61083518), we get a palindrome (81599099518).

The spelling of 81538016000 in words is "eighty-one billion, five hundred thirty-eight million, sixteen thousand".