81935321 has 4 divisors (see below), whose sum is σ = 88238052. Its totient is φ = 75632592.

The previous prime is 81935311. The next prime is 81935323. The reversal of 81935321 is 12353918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12353918 = 2 ⋅6176959.

It can be written as a sum of positive squares in 2 ways, for example, as 40513225 + 41422096 = 6365^2 + 6436^2 .

It is a cyclic number.

It is not a de Polignac number, because 81935321 - 2¹⁸ = 81673177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81935323) 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, 3151346 + ... + 3151371.

It is an arithmetic number, because the mean of its divisors is an integer number (22059513).

Almost surely, 2^81935321 is an apocalyptic number.

It is an amenable number.

81935321 is a deficient number, since it is larger than the sum of its proper divisors (6302731).

81935321 is a wasteful number, since it uses less digits than its factorization.

81935321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6302730.

The product of its digits is 6480, while the sum is 32.

The square root of 81935321 is about 9051.8131332899. The cubic root of 81935321 is about 434.3338922229. Note that the first 3 decimals are identical.

The spelling of 81935321 in words is "eighty-one million, nine hundred thirty-five thousand, three hundred twenty-one".