81440352 has 216 divisors, whose sum is σ = 280098000. Its totient is φ = 22353408.

The previous prime is 81440351. The next prime is 81440371. The reversal of 81440352 is 25304418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81440351) 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 35 ways as a sum of consecutive naturals, for example, 409149 + ... + 409347.

It is an arithmetic number, because the mean of its divisors is an integer number (1296750).

Almost surely, 2^81440352 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81440352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140049000).

81440352 is an abundant number, since it is smaller than the sum of its proper divisors (198657648).

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

81440352 is a wasteful number, since it uses less digits than its factorization.

81440352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 81440352 is about 9024.4308407788. The cubic root of 81440352 is about 433.4575254817.

The spelling of 81440352 in words is "eighty-one million, four hundred forty thousand, three hundred fifty-two".