81064120320 has 312 divisors, whose sum is σ = 283282262016. Its totient is φ = 21440692224.

The previous prime is 81064120303. The next prime is 81064120321. The reversal of 81064120320 is 2302146018.

81064120320 is a `hidden beast` number, since 8 + 10 + 641 + 2 + 0 + 3 + 2 + 0 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81064120321) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23406909 + ... + 23410371.

It is an arithmetic number, because the mean of its divisors is an integer number (907955968).

Almost surely, 2^81064120320 is an apocalyptic number.

81064120320 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 81064120320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141641131008).

81064120320 is an abundant number, since it is smaller than the sum of its proper divisors (202218141696).

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

81064120320 is a wasteful number, since it uses less digits than its factorization.

81064120320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3625 (or 3600 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

Adding to 81064120320 its reverse (2302146018), we get a palindrome (83366266338).

The spelling of 81064120320 in words is "eighty-one billion, sixty-four million, one hundred twenty thousand, three hundred twenty".