81175920 has 160 divisors (see below), whose sum is σ = 290219520. Its totient is φ = 18385920.

The previous prime is 81175907. The next prime is 81175951. The reversal of 81175920 is 2957118.

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 31 ways as a sum of consecutive naturals, for example, 354366 + ... + 354594.

It is an arithmetic number, because the mean of its divisors is an integer number (1813872).

Almost surely, 2^81175920 is an apocalyptic number.

81175920 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 81175920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145109760).

81175920 is an abundant number, since it is smaller than the sum of its proper divisors (209043600).

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

81175920 is a wasteful number, since it uses less digits than its factorization.

81175920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463 (or 457 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 33.

The square root of 81175920 is about 9009.7680325300. The cubic root of 81175920 is about 432.9878798386.

The spelling of 81175920 in words is "eighty-one million, one hundred seventy-five thousand, nine hundred twenty".