81065668 has 12 divisors (see below), whose sum is σ = 145699372. Its totient is φ = 39437280.

The previous prime is 81065659. The next prime is 81065669. The reversal of 81065668 is 86656018.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 45805824 + 35259844 = 6768^2 + 5938^2 .

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81065668.

It is not an unprimeable number, because it can be changed into a prime (81065669) 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, 273723 + ... + 274018.

Almost surely, 2^81065668 is an apocalyptic number.

It is an amenable number.

81065668 is a deficient number, since it is larger than the sum of its proper divisors (64633704).

81065668 is a wasteful number, since it uses less digits than its factorization.

81065668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547782 (or 547780 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 81065668 is about 9003.6474831037. The cubic root of 81065668 is about 432.7917649960.

The spelling of 81065668 in words is "eighty-one million, sixty-five thousand, six hundred sixty-eight".