81231461057 has 2 divisors, whose sum is σ = 81231461058. Its totient is φ = 81231461056.

The previous prime is 81231461033. The next prime is 81231461099. The reversal of 81231461057 is 75016413218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70811338816 + 10420122241 = 266104^2 + 102079^2 .

It is a cyclic number.

It is not a de Polignac number, because 81231461057 - 2¹² = 81231456961 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81231461057.

It is not a weakly prime, because it can be changed into another prime (81231464057) 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, 40615730528 + 40615730529.

It is an arithmetic number, because the mean of its divisors is an integer number (40615730529).

Almost surely, 2^81231461057 is an apocalyptic number.

It is an amenable number.

81231461057 is a deficient number, since it is larger than the sum of its proper divisors (1).

81231461057 is an equidigital number, since it uses as much as digits as its factorization.

81231461057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40320, while the sum is 38.

The spelling of 81231461057 in words is "eighty-one billion, two hundred thirty-one million, four hundred sixty-one thousand, fifty-seven".