81575359 has 2 divisors, whose sum is σ = 81575360. Its totient is φ = 81575358.

The previous prime is 81575339. The next prime is 81575369. The reversal of 81575359 is 95357518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81575359 - 2⁵ = 81575327 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81575309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40787679 + 40787680.

It is an arithmetic number, because the mean of its divisors is an integer number (40787680).

Almost surely, 2^81575359 is an apocalyptic number.

81575359 is a deficient number, since it is larger than the sum of its proper divisors (1).

81575359 is an equidigital number, since it uses as much as digits as its factorization.

81575359 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 189000, while the sum is 43.

The square root of 81575359 is about 9031.9078272533. The cubic root of 81575359 is about 433.6969133346.

The spelling of 81575359 in words is "eighty-one million, five hundred seventy-five thousand, three hundred fifty-nine".