81765875871 has 16 divisors (see below), whose sum is σ = 123951717120. Its totient is φ = 53242895160.

The previous prime is 81765875861. The next prime is 81765875899. The reversal of 81765875871 is 17857856718.

It is not a de Polignac number, because 81765875871 - 2⁵ = 81765875839 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81765875799 and 81765875808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81765875861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35212395 + ... + 35214716.

It is an arithmetic number, because the mean of its divisors is an integer number (7746982320).

Almost surely, 2^81765875871 is an apocalyptic number.

81765875871 is a deficient number, since it is larger than the sum of its proper divisors (42185841249).

81765875871 is a wasteful number, since it uses less digits than its factorization.

81765875871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70427163 (or 70427157 counting only the distinct ones).

The product of its digits is 26342400, while the sum is 63.

The spelling of 81765875871 in words is "eighty-one billion, seven hundred sixty-five million, eight hundred seventy-five thousand, eight hundred seventy-one".