81163844 has 6 divisors (see below), whose sum is σ = 142036734. Its totient is φ = 40581920.

The previous prime is 81163813. The next prime is 81163853. The reversal of 81163844 is 44836118.

It can be written as a sum of positive squares in only one way, i.e., 80317444 + 846400 = 8962^2 + 920^2 .

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, 10145477 + ... + 10145484.

It is an arithmetic number, because the mean of its divisors is an integer number (23672789).

Almost surely, 2^81163844 is an apocalyptic number.

It is an amenable number.

81163844 is a deficient number, since it is larger than the sum of its proper divisors (60872890).

81163844 is a wasteful number, since it uses less digits than its factorization.

81163844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20290965 (or 20290963 counting only the distinct ones).

The product of its digits is 18432, while the sum is 35.

The square root of 81163844 is about 9009.0978460665. The cubic root of 81163844 is about 432.9664078678.

The spelling of 81163844 in words is "eighty-one million, one hundred sixty-three thousand, eight hundred forty-four".