81823393 has 2 divisors, whose sum is σ = 81823394. Its totient is φ = 81823392.

The previous prime is 81823369. The next prime is 81823409. The reversal of 81823393 is 39332818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77299264 + 4524129 = 8792^2 + 2127^2 .

It is a cyclic number.

It is not a de Polignac number, because 81823393 - 2¹⁷ = 81692321 is a prime.

It is not a weakly prime, because it can be changed into another prime (81823333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40911696 + 40911697.

It is an arithmetic number, because the mean of its divisors is an integer number (40911697).

Almost surely, 2^81823393 is an apocalyptic number.

It is an amenable number.

81823393 is a deficient number, since it is larger than the sum of its proper divisors (1).

81823393 is an equidigital number, since it uses as much as digits as its factorization.

81823393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 37.

The square root of 81823393 is about 9045.6283916597. The cubic root of 81823393 is about 434.1360277097.

The spelling of 81823393 in words is "eighty-one million, eight hundred twenty-three thousand, three hundred ninety-three".