81834581 has 2 divisors, whose sum is σ = 81834582. Its totient is φ = 81834580.

The previous prime is 81834559. The next prime is 81834587. The reversal of 81834581 is 18543818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81180100 + 654481 = 9010^2 + 809^2 .

It is a cyclic number.

It is not a de Polignac number, because 81834581 - 2⁶ = 81834517 is a prime.

It is a super-2 number, since 2×81834581² = 13393797294891122, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81834587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40917290 + 40917291.

It is an arithmetic number, because the mean of its divisors is an integer number (40917291).

Almost surely, 2^81834581 is an apocalyptic number.

It is an amenable number.

81834581 is a deficient number, since it is larger than the sum of its proper divisors (1).

81834581 is an equidigital number, since it uses as much as digits as its factorization.

81834581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30720, while the sum is 38.

The square root of 81834581 is about 9046.2467907967. The cubic root of 81834581 is about 434.1558137894.

The spelling of 81834581 in words is "eighty-one million, eight hundred thirty-four thousand, five hundred eighty-one".