81455319549 has 20 divisors (see below), whose sum is σ = 121969246300. Its totient is φ = 54174536640.

The previous prime is 81455319541. The next prime is 81455319571. The reversal of 81455319549 is 94591355418.

81455319549 is a `hidden beast` number, since 8 + 1 + 45 + 53 + 1 + 9 + 549 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 17747035524 + 63708284025 = 133218^2 + 252405^2 .

It is not a de Polignac number, because 81455319549 - 2³ = 81455319541 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81455319495 and 81455319504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81455319541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1160224 + ... + 1228425.

It is an arithmetic number, because the mean of its divisors is an integer number (6098462315).

Almost surely, 2^81455319549 is an apocalyptic number.

It is an amenable number.

81455319549 is a deficient number, since it is larger than the sum of its proper divisors (40513926751).

81455319549 is a wasteful number, since it uses less digits than its factorization.

81455319549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2389082 (or 2389073 counting only the distinct ones).

The product of its digits is 3888000, while the sum is 54.

The spelling of 81455319549 in words is "eighty-one billion, four hundred fifty-five million, three hundred nineteen thousand, five hundred forty-nine".