81688192104439 has 4 divisors (see below), whose sum is σ = 81688214251840. Its totient is φ = 81688169957040.

The previous prime is 81688192104437. The next prime is 81688192104559. The reversal of 81688192104439 is 93440129188618.

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 81688192104439 - 2¹ = 81688192104437 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 (81688192104437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4060647 + ... + 13411384.

It is an arithmetic number, because the mean of its divisors is an integer number (20422053562960).

Almost surely, 2^{81688192104439} is an apocalyptic number.

81688192104439 is a deficient number, since it is larger than the sum of its proper divisors (22147401).

81688192104439 is a wasteful number, since it uses less digits than its factorization.

81688192104439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22147400.

The product of its (nonzero) digits is 23887872, while the sum is 64.

The spelling of 81688192104439 in words is "eighty-one trillion, six hundred eighty-eight billion, one hundred ninety-two million, one hundred four thousand, four hundred thirty-nine".