81229824 has 192 divisors, whose sum is σ = 261424800. Its totient is φ = 24772608.

The previous prime is 81229823. The next prime is 81229831. The reversal of 81229824 is 42892218.

It is a tau number, because it is divible by the number of its divisors (192).

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

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81229823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 718792 + ... + 718904.

Almost surely, 2^81229824 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 81229824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130712400).

81229824 is an abundant number, since it is smaller than the sum of its proper divisors (180194976).

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

81229824 is a wasteful number, since it uses less digits than its factorization.

81229824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157 (or 131 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 81229824 is about 9012.7589560578. The cubic root of 81229824 is about 433.0836989534.

The spelling of 81229824 in words is "eighty-one million, two hundred twenty-nine thousand, eight hundred twenty-four".