81775508599 has 2 divisors, whose sum is σ = 81775508600. Its totient is φ = 81775508598.

The previous prime is 81775508557. The next prime is 81775508609. The reversal of 81775508599 is 99580557718.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81775508599 - 2¹³ = 81775500407 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81775508599.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81775568599) 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, 40887754299 + 40887754300.

It is an arithmetic number, because the mean of its divisors is an integer number (40887754300).

Almost surely, 2^81775508599 is an apocalyptic number.

81775508599 is a deficient number, since it is larger than the sum of its proper divisors (1).

81775508599 is an equidigital number, since it uses as much as digits as its factorization.

81775508599 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31752000, while the sum is 64.

The spelling of 81775508599 in words is "eighty-one billion, seven hundred seventy-five million, five hundred eight thousand, five hundred ninety-nine".