81583872 has 72 divisors (see below), whose sum is σ = 228600960. Its totient is φ = 25758720.

The previous prime is 81583871. The next prime is 81583903. The reversal of 81583872 is 27838518.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81583871) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 11797 + ... + 17387.

Almost surely, 2^81583872 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 81583872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114300480).

81583872 is an abundant number, since it is smaller than the sum of its proper divisors (147017088).

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

81583872 is a wasteful number, since it uses less digits than its factorization.

81583872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5629 (or 5615 counting only the distinct ones).

The product of its digits is 107520, while the sum is 42.

The square root of 81583872 is about 9032.3790885901. The cubic root of 81583872 is about 433.7119993174.

The spelling of 81583872 in words is "eighty-one million, five hundred eighty-three thousand, eight hundred seventy-two".