81547868 has 6 divisors (see below), whose sum is σ = 142708776. Its totient is φ = 40773932.

The previous prime is 81547859. The next prime is 81547891. The reversal of 81547868 is 86874518.

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 (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10193480 + ... + 10193487.

It is an arithmetic number, because the mean of its divisors is an integer number (23784796).

Almost surely, 2^81547868 is an apocalyptic number.

It is an amenable number.

81547868 is a deficient number, since it is larger than the sum of its proper divisors (61160908).

81547868 is a wasteful number, since it uses less digits than its factorization.

81547868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20386971 (or 20386969 counting only the distinct ones).

The product of its digits is 430080, while the sum is 47.

The square root of 81547868 is about 9030.3858167855. The cubic root of 81547868 is about 433.6481890565.

The spelling of 81547868 in words is "eighty-one million, five hundred forty-seven thousand, eight hundred sixty-eight".