81133844 has 24 divisors (see below), whose sum is σ = 158191488. Its totient is φ = 36093440.

The previous prime is 81133837. The next prime is 81133853. The reversal of 81133844 is 44833118.

It is a self number, because there is not a number n which added to its sum of digits gives 81133844.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17549 + ... + 21684.

It is an arithmetic number, because the mean of its divisors is an integer number (6591312).

Almost surely, 2^81133844 is an apocalyptic number.

It is an amenable number.

81133844 is a deficient number, since it is larger than the sum of its proper divisors (77057644).

81133844 is a wasteful number, since it uses less digits than its factorization.

81133844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39295 (or 39293 counting only the distinct ones).

The product of its digits is 9216, while the sum is 32.

The square root of 81133844 is about 9007.4327086024. The cubic root of 81133844 is about 432.9130565550.

The spelling of 81133844 in words is "eighty-one million, one hundred thirty-three thousand, eight hundred forty-four".