81729883 has 4 divisors (see below), whose sum is σ = 82949800. Its totient is φ = 80509968.

The previous prime is 81729881. The next prime is 81729889. The reversal of 81729883 is 38892718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 38892718 = 2 ⋅19446359.

It is a cyclic number.

It is not a de Polignac number, because 81729883 - 2¹ = 81729881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81729881) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 609858 + ... + 609991.

It is an arithmetic number, because the mean of its divisors is an integer number (20737450).

Almost surely, 2^81729883 is an apocalyptic number.

81729883 is a deficient number, since it is larger than the sum of its proper divisors (1219917).

81729883 is a wasteful number, since it uses less digits than its factorization.

81729883 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1219916.

The product of its digits is 193536, while the sum is 46.

The square root of 81729883 is about 9040.4581189230. The cubic root of 81729883 is about 433.9705838472.

The spelling of 81729883 in words is "eighty-one million, seven hundred twenty-nine thousand, eight hundred eighty-three".