81681091169 has 8 divisors (see below), whose sum is σ = 81739409280. Its totient is φ = 81622800000.

The previous prime is 81681091123. The next prime is 81681091171. The reversal of 81681091169 is 96119018618.

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 81681091169 - 2⁸ = 81681090913 is a prime.

It is a super-2 number, since 2×81681091169² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81681091199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13276244 + ... + 13282394.

It is an arithmetic number, because the mean of its divisors is an integer number (10217426160).

Almost surely, 2^81681091169 is an apocalyptic number.

It is an amenable number.

81681091169 is a deficient number, since it is larger than the sum of its proper divisors (58318111).

81681091169 is a wasteful number, since it uses less digits than its factorization.

81681091169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13471.

The product of its (nonzero) digits is 186624, while the sum is 50.

The spelling of 81681091169 in words is "eighty-one billion, six hundred eighty-one million, ninety-one thousand, one hundred sixty-nine".