81183744 has 132 divisors (see below), whose sum is σ = 245246976. Its totient is φ = 25817088.

The previous prime is 81183733. The next prime is 81183769. The reversal of 81183744 is 44738118.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81183699 and 81183708.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 211777 + ... + 212159.

Almost surely, 2^81183744 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81183744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122623488).

81183744 is an abundant number, since it is smaller than the sum of its proper divisors (164063232).

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

81183744 is a wasteful number, since it uses less digits than its factorization.

81183744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432 (or 411 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 81183744 is about 9010.2022174866. The cubic root of 81183744 is about 433.0017903199.

The spelling of 81183744 in words is "eighty-one million, one hundred eighty-three thousand, seven hundred forty-four".