81688192104437 has 2 divisors, whose sum is σ = 81688192104438. Its totient is φ = 81688192104436.

The previous prime is 81688192104391. The next prime is 81688192104559. The reversal of 81688192104437 is 73440129188618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81687052771921 + 1139332516 = 9038089^2 + 33754^2 .

It is a cyclic number.

It is not a de Polignac number, because 81688192104437 - 2¹⁴ = 81688192088053 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81688192104437.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81688192104137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40844096052218 + 40844096052219.

It is an arithmetic number, because the mean of its divisors is an integer number (40844096052219).

Almost surely, 2^{81688192104437} is an apocalyptic number.

It is an amenable number.

81688192104437 is a deficient number, since it is larger than the sum of its proper divisors (1).

81688192104437 is an equidigital number, since it uses as much as digits as its factorization.

81688192104437 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18579456, while the sum is 62.

The spelling of 81688192104437 in words is "eighty-one trillion, six hundred eighty-eight billion, one hundred ninety-two million, one hundred four thousand, four hundred thirty-seven".