81445120 has 36 divisors (see below), whose sum is σ = 195089580. Its totient is φ = 32577536.

The previous prime is 81445109. The next prime is 81445121. The reversal of 81445120 is 2154418.

It can be written as a sum of positive squares in 2 ways, for example, as 30294016 + 51151104 = 5504^2 + 7152^2 .

It is not an unprimeable number, because it can be changed into a prime (81445121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30535 + ... + 33094.

It is an arithmetic number, because the mean of its divisors is an integer number (5419155).

Almost surely, 2^81445120 is an apocalyptic number.

81445120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81445120 is an abundant number, since it is smaller than the sum of its proper divisors (113644460).

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

81445120 is an equidigital number, since it uses as much as digits as its factorization.

81445120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63650 (or 63636 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 25.

The square root of 81445120 is about 9024.6950086970. The cubic root of 81445120 is about 433.4659843726.

Adding to 81445120 its reverse (2154418), we get a palindrome (83599538).

The spelling of 81445120 in words is "eighty-one million, four hundred forty-five thousand, one hundred twenty".