81743999 has 2 divisors, whose sum is σ = 81744000. Its totient is φ = 81743998.

The previous prime is 81743983. The next prime is 81744029. The reversal of 81743999 is 99934718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81743999 - 2⁴ = 81743983 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81743929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40871999 + 40872000.

It is an arithmetic number, because the mean of its divisors is an integer number (40872000).

Almost surely, 2^81743999 is an apocalyptic number.

81743999 is a deficient number, since it is larger than the sum of its proper divisors (1).

81743999 is an equidigital number, since it uses as much as digits as its factorization.

81743999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 50.

The square root of 81743999 is about 9041.2387978639. The cubic root of 81743999 is about 433.9955668599.

The spelling of 81743999 in words is "eighty-one million, seven hundred forty-three thousand, nine hundred ninety-nine".