81477756904871 has 8 divisors (see below), whose sum is σ = 85137214815744. Its totient is φ = 77828044555800.

The previous prime is 81477756904793. The next prime is 81477756904897. The reversal of 81477756904871 is 17840965777418.

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

It is a cyclic number.

It is not a de Polignac number, because 81477756904871 - 2¹⁸ = 81477756642727 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81477756924871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2436373355 + ... + 2436406796.

It is an arithmetic number, because the mean of its divisors is an integer number (10642151851968).

Almost surely, 2^{81477756904871} is an apocalyptic number.

81477756904871 is a deficient number, since it is larger than the sum of its proper divisors (3659457910873).

81477756904871 is a wasteful number, since it uses less digits than its factorization.

81477756904871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4872780901.

The product of its (nonzero) digits is 663828480, while the sum is 74.

The spelling of 81477756904871 in words is "eighty-one trillion, four hundred seventy-seven billion, seven hundred fifty-six million, nine hundred four thousand, eight hundred seventy-one".