81833813 has 2 divisors, whose sum is σ = 81833814. Its totient is φ = 81833812.

The previous prime is 81833789. The next prime is 81833863. The reversal of 81833813 is 31833818.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55383364 + 26450449 = 7442^2 + 5143^2 .

It is a cyclic number.

It is not a de Polignac number, because 81833813 - 2²² = 77639509 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81833863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40916906 + 40916907.

It is an arithmetic number, because the mean of its divisors is an integer number (40916907).

Almost surely, 2^81833813 is an apocalyptic number.

It is an amenable number.

81833813 is a deficient number, since it is larger than the sum of its proper divisors (1).

81833813 is an equidigital number, since it uses as much as digits as its factorization.

81833813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 35.

The square root of 81833813 is about 9046.2043421537. The cubic root of 81833813 is about 434.1544556321.

The spelling of 81833813 in words is "eighty-one million, eight hundred thirty-three thousand, eight hundred thirteen".