81443871 has 12 divisors (see below), whose sum is σ = 117765648. Its totient is φ = 54238464.

The previous prime is 81443867. The next prime is 81443909. The reversal of 81443871 is 17834418.

It is not a de Polignac number, because 81443871 - 2² = 81443867 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81423871) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5311 + ... + 13823.

It is an arithmetic number, because the mean of its divisors is an integer number (9813804).

Almost surely, 2^81443871 is an apocalyptic number.

81443871 is a deficient number, since it is larger than the sum of its proper divisors (36321777).

81443871 is a wasteful number, since it uses less digits than its factorization.

81443871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9582 (or 9579 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 81443871 is about 9024.6258094173. The cubic root of 81443871 is about 433.4637685583.

The spelling of 81443871 in words is "eighty-one million, four hundred forty-three thousand, eight hundred seventy-one".