81138068 has 24 divisors (see below), whose sum is σ = 156280320. Its totient is φ = 36552320.

The previous prime is 81138049. The next prime is 81138073. The reversal of 81138068 is 86083118.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3188 + ... + 13131.

It is an arithmetic number, because the mean of its divisors is an integer number (6511680).

Almost surely, 2^81138068 is an apocalyptic number.

It is an amenable number.

81138068 is a deficient number, since it is larger than the sum of its proper divisors (75142252).

81138068 is a wasteful number, since it uses less digits than its factorization.

81138068 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16447 (or 16445 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 81138068 is about 9007.6671785763. The cubic root of 81138068 is about 432.9205692152.

The spelling of 81138068 in words is "eighty-one million, one hundred thirty-eight thousand, sixty-eight".