81489375593 has 2 divisors, whose sum is σ = 81489375594. Its totient is φ = 81489375592.

The previous prime is 81489375533. The next prime is 81489375677. The reversal of 81489375593 is 39557398418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80580473689 + 908901904 = 283867^2 + 30148^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81489375593 is a prime.

It is not a weakly prime, because it can be changed into another prime (81489375533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40744687796 + 40744687797.

It is an arithmetic number, because the mean of its divisors is an integer number (40744687797).

Almost surely, 2^81489375593 is an apocalyptic number.

It is an amenable number.

81489375593 is a deficient number, since it is larger than the sum of its proper divisors (1).

81489375593 is an equidigital number, since it uses as much as digits as its factorization.

81489375593 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32659200, while the sum is 62.

The spelling of 81489375593 in words is "eighty-one billion, four hundred eighty-nine million, three hundred seventy-five thousand, five hundred ninety-three".