81136668 has 24 divisors (see below), whose sum is σ = 189487872. Its totient is φ = 27021424.

The previous prime is 81136667. The next prime is 81136687. The reversal of 81136668 is 86663118.

81136668 is digitally balanced in base 9, because in such base it contains all the possibile digits an equal number of times.

81136668 is strictly pandigital in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81136661) by changing a digit.

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, 15571 + ... + 20117.

It is an arithmetic number, because the mean of its divisors is an integer number (7895328).

Almost surely, 2^81136668 is an apocalyptic number.

It is an amenable number.

81136668 is an abundant number, since it is smaller than the sum of its proper divisors (108351204).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81136668 is a wasteful number, since it uses less digits than its factorization.

81136668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6041 (or 6039 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 81136668 is about 9007.5894666664. The cubic root of 81136668 is about 432.9180792526.

The spelling of 81136668 in words is "eighty-one million, one hundred thirty-six thousand, six hundred sixty-eight".