81054384865 has 16 divisors (see below), whose sum is σ = 97547622480. Its totient is φ = 64655539200.

The previous prime is 81054384857. The next prime is 81054384877. The reversal of 81054384865 is 56848345018.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 3552279201 + 77502105664 = 59601^2 + 278392^2 .

It is not a de Polignac number, because 81054384865 - 2³ = 81054384857 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2474877 + ... + 2507413.

It is an arithmetic number, because the mean of its divisors is an integer number (6096726405).

Almost surely, 2^81054384865 is an apocalyptic number.

It is an amenable number.

81054384865 is a deficient number, since it is larger than the sum of its proper divisors (16493237615).

81054384865 is a wasteful number, since it uses less digits than its factorization.

81054384865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33972.

The product of its (nonzero) digits is 3686400, while the sum is 52.

The spelling of 81054384865 in words is "eighty-one billion, fifty-four million, three hundred eighty-four thousand, eight hundred sixty-five".