81544805271 has 20 divisors (see below), whose sum is σ = 123482536672. Its totient is φ = 53618498208.

The previous prime is 81544805269. The next prime is 81544805281. The reversal of 81544805271 is 17250844518.

81544805271 is a `hidden beast` number, since 8 + 1 + 5 + 44 + 80 + 527 + 1 = 666.

It is not a de Polignac number, because 81544805271 - 2¹ = 81544805269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81544805281) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6889471 + ... + 6901296.

Almost surely, 2^81544805271 is an apocalyptic number.

81544805271 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81544805271 is a deficient number, since it is larger than the sum of its proper divisors (41937731401).

81544805271 is a wasteful number, since it uses less digits than its factorization.

81544805271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13790852 (or 13790843 counting only the distinct ones).

The product of its (nonzero) digits is 358400, while the sum is 45.

The spelling of 81544805271 in words is "eighty-one billion, five hundred forty-four million, eight hundred five thousand, two hundred seventy-one".