81807079 has 2 divisors, whose sum is σ = 81807080. Its totient is φ = 81807078.

The previous prime is 81807059. The next prime is 81807091. The reversal of 81807079 is 97070818.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81807079 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81807049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40903539 + 40903540.

It is an arithmetic number, because the mean of its divisors is an integer number (40903540).

Almost surely, 2^81807079 is an apocalyptic number.

81807079 is a deficient number, since it is larger than the sum of its proper divisors (1).

81807079 is an equidigital number, since it uses as much as digits as its factorization.

81807079 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 40.

The square root of 81807079 is about 9044.7265851434. The cubic root of 81807079 is about 434.1071730197.

The spelling of 81807079 in words is "eighty-one million, eight hundred seven thousand, seventy-nine".