81040081447 has 4 divisors (see below), whose sum is σ = 87273933880. Its totient is φ = 74806229016.

The previous prime is 81040081439. The next prime is 81040081453. The reversal of 81040081447 is 74418004018.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81040081447 - 2³ = 81040081439 is a prime.

It is a super-2 number, since 2×81040081447² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81040081247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3116926197 + ... + 3116926222.

It is an arithmetic number, because the mean of its divisors is an integer number (21818483470).

Almost surely, 2^81040081447 is an apocalyptic number.

81040081447 is a deficient number, since it is larger than the sum of its proper divisors (6233852433).

81040081447 is a wasteful number, since it uses less digits than its factorization.

81040081447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6233852432.

The product of its (nonzero) digits is 28672, while the sum is 37.

The spelling of 81040081447 in words is "eighty-one billion, forty million, eighty-one thousand, four hundred forty-seven".