81085432357 has 2 divisors, whose sum is σ = 81085432358. Its totient is φ = 81085432356.

The previous prime is 81085432291. The next prime is 81085432361. The reversal of 81085432357 is 75323458018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72806070276 + 8279362081 = 269826^2 + 90991^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81085432357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81085432367) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40542716178 + 40542716179.

It is an arithmetic number, because the mean of its divisors is an integer number (40542716179).

Almost surely, 2^81085432357 is an apocalyptic number.

It is an amenable number.

81085432357 is a deficient number, since it is larger than the sum of its proper divisors (1).

81085432357 is an equidigital number, since it uses as much as digits as its factorization.

81085432357 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 806400, while the sum is 46.

The spelling of 81085432357 in words is "eighty-one billion, eighty-five million, four hundred thirty-two thousand, three hundred fifty-seven".