81946571 has 6 divisors (see below), whose sum is σ = 95325660. Its totient is φ = 70239876.

The previous prime is 81946559. The next prime is 81946597. The reversal of 81946571 is 17564918.

It is not a de Polignac number, because 81946571 - 2¹⁰ = 81945547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81946531) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 836141 + ... + 836238.

It is an arithmetic number, because the mean of its divisors is an integer number (15887610).

Almost surely, 2^81946571 is an apocalyptic number.

81946571 is a deficient number, since it is larger than the sum of its proper divisors (13379089).

81946571 is a wasteful number, since it uses less digits than its factorization.

81946571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1672393 (or 1672386 counting only the distinct ones).

The product of its digits is 60480, while the sum is 41.

The square root of 81946571 is about 9052.4345344222. The cubic root of 81946571 is about 434.3537698231.

The spelling of 81946571 in words is "eighty-one million, nine hundred forty-six thousand, five hundred seventy-one".