81042253461457 has 2 divisors, whose sum is σ = 81042253461458. Its totient is φ = 81042253461456.

The previous prime is 81042253461427. The next prime is 81042253461473. The reversal of 81042253461457 is 75416435224018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75206376409921 + 5835877051536 = 8672161^2 + 2415756^2 .

It is a cyclic number.

It is not a de Polignac number, because 81042253461457 - 2²³ = 81042245072849 is a prime.

It is a super-2 number, since 2×81042253461457² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81042253461427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40521126730728 + 40521126730729.

It is an arithmetic number, because the mean of its divisors is an integer number (40521126730729).

Almost surely, 2^{81042253461457} is an apocalyptic number.

It is an amenable number.

81042253461457 is a deficient number, since it is larger than the sum of its proper divisors (1).

81042253461457 is an equidigital number, since it uses as much as digits as its factorization.

81042253461457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6451200, while the sum is 52.

The spelling of 81042253461457 in words is "eighty-one trillion, forty-two billion, two hundred fifty-three million, four hundred sixty-one thousand, four hundred fifty-seven".