81180320 has 96 divisors (see below), whose sum is σ = 213373440. Its totient is φ = 28984320.

The previous prime is 81180313. The next prime is 81180329. The reversal of 81180320 is 2308118.

It is not an unprimeable number, because it can be changed into a prime (81180329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63851 + ... + 65109.

It is an arithmetic number, because the mean of its divisors is an integer number (2222640).

Almost surely, 2^81180320 is an apocalyptic number.

81180320 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 81180320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106686720).

81180320 is an abundant number, since it is smaller than the sum of its proper divisors (132193120).

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

81180320 is a wasteful number, since it uses less digits than its factorization.

81180320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1318 (or 1310 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 81180320 is about 9010.0122086488. The cubic root of 81180320 is about 432.9957028164.

Adding to 81180320 its reverse (2308118), we get a palindrome (83488438).

The spelling of 81180320 in words is "eighty-one million, one hundred eighty thousand, three hundred twenty".