81904480 has 144 divisors (see below), whose sum is σ = 233041536. Its totient is φ = 27095040.

The previous prime is 81904477. The next prime is 81904481. The reversal of 81904480 is 8440918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81904481) 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 23 ways as a sum of consecutive naturals, for example, 242872 + ... + 243208.

It is an arithmetic number, because the mean of its divisors is an integer number (1618344).

Almost surely, 2^81904480 is an apocalyptic number.

81904480 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 81904480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116520768).

81904480 is an abundant number, since it is smaller than the sum of its proper divisors (151137056).

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

81904480 is a wasteful number, since it uses less digits than its factorization.

81904480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397 (or 382 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 81904480 is about 9050.1093916041. The cubic root of 81904480 is about 434.2793899950.

The spelling of 81904480 in words is "eighty-one million, nine hundred four thousand, four hundred eighty".