81168745 has 12 divisors (see below), whose sum is σ = 113305284. Its totient is φ = 55658400.

The previous prime is 81168743. The next prime is 81168749. The reversal of 81168745 is 54786118.

It can be written as a sum of positive squares in 2 ways, for example, as 61905424 + 19263321 = 7868^2 + 4389^2 .

It is not a de Polignac number, because 81168745 - 2¹ = 81168743 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81168698 and 81168707.

It is not an unprimeable number, because it can be changed into a prime (81168743) 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 11 ways as a sum of consecutive naturals, for example, 165406 + ... + 165895.

It is an arithmetic number, because the mean of its divisors is an integer number (9442107).

Almost surely, 2^81168745 is an apocalyptic number.

It is an amenable number.

81168745 is a deficient number, since it is larger than the sum of its proper divisors (32136539).

81168745 is a wasteful number, since it uses less digits than its factorization.

81168745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331320 (or 331313 counting only the distinct ones).

The product of its digits is 53760, while the sum is 40.

The square root of 81168745 is about 9009.3698447783. The cubic root of 81168745 is about 432.9751224446.

It can be divided in two parts, 8116 and 8745, that added together give a palindrome (16861).

The spelling of 81168745 in words is "eighty-one million, one hundred sixty-eight thousand, seven hundred forty-five".