81332160 has 448 divisors, whose sum is σ = 341376000. Its totient is φ = 16257024.

The previous prime is 81332143. The next prime is 81332161. The reversal of 81332160 is 6123318.

It is a tau number, because it is divible by the number of its divisors (448).

It is a super-2 number, since 2×81332160² = 13229840500531200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 81332160.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81332161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4280631 + ... + 4280649.

It is an arithmetic number, because the mean of its divisors is an integer number (762000).

Almost surely, 2^81332160 is an apocalyptic number.

81332160 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 81332160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170688000).

81332160 is an abundant number, since it is smaller than the sum of its proper divisors (260043840).

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

81332160 is a wasteful number, since it uses less digits than its factorization.

81332160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73 (or 49 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 81332160 is about 9018.4344539393. The cubic root of 81332160 is about 433.2654936535.

Adding to 81332160 its reverse (6123318), we get a palindrome (87455478).

The spelling of 81332160 in words is "eighty-one million, three hundred thirty-two thousand, one hundred sixty".