81385211040 has 384 divisors, whose sum is σ = 311426519040. Its totient is φ = 17450754048.

The previous prime is 81385210987. The next prime is 81385211041. The reversal of 81385211040 is 4011258318.

It is a junction number, because it is equal to n+sod(n) for n = 81385210992 and 81385211010.

It is not an unprimeable number, because it can be changed into a prime (81385211041) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 6569332 + ... + 6581708.

It is an arithmetic number, because the mean of its divisors is an integer number (811006560).

Almost surely, 2^81385211040 is an apocalyptic number.

81385211040 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 81385211040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155713259520).

81385211040 is an abundant number, since it is smaller than the sum of its proper divisors (230041308000).

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

81385211040 is a wasteful number, since it uses less digits than its factorization.

81385211040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12524 (or 12516 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 33.

Adding to 81385211040 its reverse (4011258318), we get a palindrome (85396469358).

The spelling of 81385211040 in words is "eighty-one billion, three hundred eighty-five million, two hundred eleven thousand, forty".