81544038111905 has 8 divisors (see below), whose sum is σ = 97852894219584. Its totient is φ = 65235198166000.

The previous prime is 81544038111869. The next prime is 81544038111953. The reversal of 81544038111905 is 50911183044518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81544038111905 - 2¹⁰ = 81544038110881 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17478590 + ... + 21646920.

It is an arithmetic number, because the mean of its divisors is an integer number (12231611777448).

Almost surely, 2^{81544038111905} is an apocalyptic number.

It is an amenable number.

81544038111905 is a deficient number, since it is larger than the sum of its proper divisors (16308856107679).

81544038111905 is a wasteful number, since it uses less digits than its factorization.

81544038111905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8080887.

The product of its (nonzero) digits is 691200, while the sum is 50.

The spelling of 81544038111905 in words is "eighty-one trillion, five hundred forty-four billion, thirty-eight million, one hundred eleven thousand, nine hundred five".