81447144 has 32 divisors (see below), whose sum is σ = 203932320. Its totient is φ = 27107136.

The previous prime is 81447131. The next prime is 81447151. The reversal of 81447144 is 44174418.

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 7 ways as a sum of consecutive naturals, for example, 15927 + ... + 20409.

It is an arithmetic number, because the mean of its divisors is an integer number (6372885).

Almost surely, 2^81447144 is an apocalyptic number.

It is an amenable number.

81447144 is an abundant number, since it is smaller than the sum of its proper divisors (122485176).

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

81447144 is a wasteful number, since it uses less digits than its factorization.

81447144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5249 (or 5245 counting only the distinct ones).

The product of its digits is 14336, while the sum is 33.

The square root of 81447144 is about 9024.8071447538. The cubic root of 81447144 is about 433.4695750436.

The spelling of 81447144 in words is "eighty-one million, four hundred forty-seven thousand, one hundred forty-four".