81729323 has 8 divisors (see below), whose sum is σ = 89006400. Its totient is φ = 74593728.

The previous prime is 81729313. The next prime is 81729343. The reversal of 81729323 is 32392718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81729323 - 2⁶ = 81729259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81729313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34163 + ... + 36476.

It is an arithmetic number, because the mean of its divisors is an integer number (11125800).

Almost surely, 2^81729323 is an apocalyptic number.

81729323 is a deficient number, since it is larger than the sum of its proper divisors (7277077).

81729323 is a wasteful number, since it uses less digits than its factorization.

81729323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70741.

The product of its digits is 18144, while the sum is 35.

The square root of 81729323 is about 9040.4271469881. The cubic root of 81729323 is about 433.9695926795.

The spelling of 81729323 in words is "eighty-one million, seven hundred twenty-nine thousand, three hundred twenty-three".