81504480 has 96 divisors (see below), whose sum is σ = 258086304. Its totient is φ = 21620736.

The previous prime is 81504463. The next prime is 81504491. The reversal of 81504480 is 8440518.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

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, 132654 + ... + 133266.

It is an arithmetic number, because the mean of its divisors is an integer number (2688399).

Almost surely, 2^81504480 is an apocalyptic number.

81504480 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 81504480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129043152).

81504480 is an abundant number, since it is smaller than the sum of its proper divisors (176581824).

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

81504480 is a wasteful number, since it uses less digits than its factorization.

81504480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 908 (or 900 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 81504480 is about 9027.9831634757. The cubic root of 81504480 is about 433.5712670965.

Adding to 81504480 its reverse (8440518), we get a palindrome (89944998).

The spelling of 81504480 in words is "eighty-one million, five hundred four thousand, four hundred eighty".