81457431773 has 2 divisors, whose sum is σ = 81457431774. Its totient is φ = 81457431772.

The previous prime is 81457431709. The next prime is 81457431799. The reversal of 81457431773 is 37713475418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74672120644 + 6785311129 = 273262^2 + 82373^2 .

It is a cyclic number.

It is not a de Polignac number, because 81457431773 - 2⁶ = 81457431709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81457433773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40728715886 + 40728715887.

It is an arithmetic number, because the mean of its divisors is an integer number (40728715887).

Almost surely, 2^81457431773 is an apocalyptic number.

It is an amenable number.

81457431773 is a deficient number, since it is larger than the sum of its proper divisors (1).

81457431773 is an equidigital number, since it uses as much as digits as its factorization.

81457431773 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1975680, while the sum is 50.

The spelling of 81457431773 in words is "eighty-one billion, four hundred fifty-seven million, four hundred thirty-one thousand, seven hundred seventy-three".