81059399 has 2 divisors, whose sum is σ = 81059400. Its totient is φ = 81059398.

The previous prime is 81059371. The next prime is 81059413. The reversal of 81059399 is 99395018.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81059399 - 2¹⁶ = 80993863 is a prime.

It is a Sophie Germain 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 (81059299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40529699 + 40529700.

It is an arithmetic number, because the mean of its divisors is an integer number (40529700).

Almost surely, 2^81059399 is an apocalyptic number.

81059399 is a deficient number, since it is larger than the sum of its proper divisors (1).

81059399 is an equidigital number, since it uses as much as digits as its factorization.

81059399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 87480, while the sum is 44.

The square root of 81059399 is about 9003.2993396865. The cubic root of 81059399 is about 432.7806084379.

The spelling of 81059399 in words is "eighty-one million, fifty-nine thousand, three hundred ninety-nine".