81143972871 has 32 divisors (see below), whose sum is σ = 117811303680. Its totient is φ = 49381761024.

The previous prime is 81143972831. The next prime is 81143972887. The reversal of 81143972871 is 17827934118.

It is not a de Polignac number, because 81143972871 - 2¹¹ = 81143970823 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81143972821) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1364076 + ... + 1422318.

It is an arithmetic number, because the mean of its divisors is an integer number (3681603240).

Almost surely, 2^81143972871 is an apocalyptic number.

81143972871 is a deficient number, since it is larger than the sum of its proper divisors (36667330809).

81143972871 is a wasteful number, since it uses less digits than its factorization.

81143972871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58655.

The product of its digits is 677376, while the sum is 51.

The spelling of 81143972871 in words is "eighty-one billion, one hundred forty-three million, nine hundred seventy-two thousand, eight hundred seventy-one".