81984193 has 4 divisors (see below), whose sum is σ = 84200020. Its totient is φ = 79768368.

The previous prime is 81984191. The next prime is 81984211. The reversal of 81984193 is 39148918.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 40870449 + 41113744 = 6393^2 + 6412^2 .

It is a cyclic number.

It is not a de Polignac number, because 81984193 - 2¹ = 81984191 is a prime.

It is a super-2 number, since 2×81984193² = 13442815803722498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81984191) 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, 1107858 + ... + 1107931.

It is an arithmetic number, because the mean of its divisors is an integer number (21050005).

Almost surely, 2^81984193 is an apocalyptic number.

It is an amenable number.

81984193 is a deficient number, since it is larger than the sum of its proper divisors (2215827).

81984193 is a wasteful number, since it uses less digits than its factorization.

81984193 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2215826.

The product of its digits is 62208, while the sum is 43.

The square root of 81984193 is about 9054.5123005052. The cubic root of 81984193 is about 434.4202308403.

The spelling of 81984193 in words is "eighty-one million, nine hundred eighty-four thousand, one hundred ninety-three".