81754766865 has 12 divisors (see below), whose sum is σ = 141708262644. Its totient is φ = 43602542304.

The previous prime is 81754766831. The next prime is 81754766879. The reversal of 81754766865 is 56866745718.

81754766865 is a `hidden beast` number, since 8 + 1 + 7 + 547 + 6 + 6 + 86 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 34932731409 + 46822035456 = 186903^2 + 216384^2 .

It is not a de Polignac number, because 81754766865 - 2³⁶ = 13035290129 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 908386254 + ... + 908386343.

It is an arithmetic number, because the mean of its divisors is an integer number (11809021887).

Almost surely, 2^81754766865 is an apocalyptic number.

It is an amenable number.

81754766865 is a deficient number, since it is larger than the sum of its proper divisors (59953495779).

81754766865 is a wasteful number, since it uses less digits than its factorization.

81754766865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1816772608 (or 1816772605 counting only the distinct ones).

The product of its digits is 67737600, while the sum is 63.

The spelling of 81754766865 in words is "eighty-one billion, seven hundred fifty-four million, seven hundred sixty-six thousand, eight hundred sixty-five".