81729324 has 60 divisors (see below), whose sum is σ = 214927944. Its totient is φ = 27081216.

The previous prime is 81729313. The next prime is 81729343. The reversal of 81729324 is 42392718.

It is a super-3 number, since 3×81729324³ (a number of 25 digits) contains 333 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 61879 + ... + 63185.

Almost surely, 2^81729324 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 81729324, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107463972).

81729324 is an abundant number, since it is smaller than the sum of its proper divisors (133198620).

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

81729324 is a wasteful number, since it uses less digits than its factorization.

81729324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1516 (or 1505 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 81729324 is about 9040.4272022953. The cubic root of 81729324 is about 433.9695944494.

The spelling of 81729324 in words is "eighty-one million, seven hundred twenty-nine thousand, three hundred twenty-four".