81934217 has 6 divisors (see below), whose sum is σ = 82424862. Its totient is φ = 81444992.

The previous prime is 81934189. The next prime is 81934241. The reversal of 81934217 is 71243918.

It can be written as a sum of positive squares in 3 ways, for example, as 9616201 + 72318016 = 3101^2 + 8504^2 .

It is not a de Polignac number, because 81934217 - 2¹⁴ = 81917833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81934117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 137873 + ... + 138465.

It is an arithmetic number, because the mean of its divisors is an integer number (13737477).

Almost surely, 2^81934217 is an apocalyptic number.

It is an amenable number.

81934217 is a deficient number, since it is larger than the sum of its proper divisors (490645).

81934217 is an frugal number, since it uses more digits than its factorization.

81934217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1419 (or 826 counting only the distinct ones).

The product of its digits is 12096, while the sum is 35.

The square root of 81934217 is about 9051.7521508269. The cubic root of 81934217 is about 434.3319414697.

The spelling of 81934217 in words is "eighty-one million, nine hundred thirty-four thousand, two hundred seventeen".