81044505 has 24 divisors (see below), whose sum is σ = 140779080. Its totient is φ = 43130880.

The previous prime is 81044503. The next prime is 81044533. The reversal of 81044505 is 50544018.

It can be written as a sum of positive squares in 4 ways, for example, as 3674889 + 77369616 = 1917^2 + 8796^2 .

It is not a de Polignac number, because 81044505 - 2¹ = 81044503 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81044501) 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, 22681 + ... + 26009.

It is an arithmetic number, because the mean of its divisors is an integer number (5865795).

Almost surely, 2^81044505 is an apocalyptic number.

It is an amenable number.

81044505 is a deficient number, since it is larger than the sum of its proper divisors (59734575).

81044505 is a wasteful number, since it uses less digits than its factorization.

81044505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3881 (or 3878 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 81044505 is about 9002.4721604679. The cubic root of 81044505 is about 432.7541001847.

The spelling of 81044505 in words is "eighty-one million, forty-four thousand, five hundred five".