81118439 has 2 divisors, whose sum is σ = 81118440. Its totient is φ = 81118438.

The previous prime is 81118421. The next prime is 81118463. The reversal of 81118439 is 93481118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81118439 - 2¹² = 81114343 is a prime.

It is a super-2 number, since 2×81118439² = 13160402291593442, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81118399 and 81118408.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81118409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40559219 + 40559220.

It is an arithmetic number, because the mean of its divisors is an integer number (40559220).

Almost surely, 2^81118439 is an apocalyptic number.

81118439 is a deficient number, since it is larger than the sum of its proper divisors (1).

81118439 is an equidigital number, since it uses as much as digits as its factorization.

81118439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 35.

The square root of 81118439 is about 9006.5775408864. The cubic root of 81118439 is about 432.8856555452.

The spelling of 81118439 in words is "eighty-one million, one hundred eighteen thousand, four hundred thirty-nine".