81457638289 has 2 divisors, whose sum is σ = 81457638290. Its totient is φ = 81457638288.

The previous prime is 81457638253. The next prime is 81457638433. The reversal of 81457638289 is 98283675418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48749107264 + 32708531025 = 220792^2 + 180855^2 .

It is a cyclic number.

It is not a de Polignac number, because 81457638289 - 2¹¹ = 81457636241 is a prime.

It is not a weakly prime, because it can be changed into another prime (81457635289) 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, 40728819144 + 40728819145.

It is an arithmetic number, because the mean of its divisors is an integer number (40728819145).

Almost surely, 2^81457638289 is an apocalyptic number.

It is an amenable number.

81457638289 is a deficient number, since it is larger than the sum of its proper divisors (1).

81457638289 is an equidigital number, since it uses as much as digits as its factorization.

81457638289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23224320, while the sum is 61.

The spelling of 81457638289 in words is "eighty-one billion, four hundred fifty-seven million, six hundred thirty-eight thousand, two hundred eighty-nine".