81323424 has 288 divisors, whose sum is σ = 297198720. Its totient is φ = 20514816.

The previous prime is 81323419. The next prime is 81323443. The reversal of 81323424 is 42432318.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×81323424² = 13226998582167552, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 759979 + ... + 760085.

It is an arithmetic number, because the mean of its divisors is an integer number (1031940).

Almost surely, 2^81323424 is an apocalyptic number.

81323424 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81323424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148599360).

81323424 is an abundant number, since it is smaller than the sum of its proper divisors (215875296).

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

81323424 is a wasteful number, since it uses less digits than its factorization.

81323424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172 (or 161 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

The square root of 81323424 is about 9017.9500996623. The cubic root of 81323424 is about 433.2499805491.

The spelling of 81323424 in words is "eighty-one million, three hundred twenty-three thousand, four hundred twenty-four".