81107751257443 has 2 divisors, whose sum is σ = 81107751257444. Its totient is φ = 81107751257442.

The previous prime is 81107751257371. The next prime is 81107751257473. The reversal of 81107751257443 is 34475215770118.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81107751257443 is a prime.

It is not a weakly prime, because it can be changed into another prime (81107751257473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40553875628721 + 40553875628722.

It is an arithmetic number, because the mean of its divisors is an integer number (40553875628722).

Almost surely, 2^{81107751257443} is an apocalyptic number.

81107751257443 is a deficient number, since it is larger than the sum of its proper divisors (1).

81107751257443 is an equidigital number, since it uses as much as digits as its factorization.

81107751257443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6585600, while the sum is 55.

The spelling of 81107751257443 in words is "eighty-one trillion, one hundred seven billion, seven hundred fifty-one million, two hundred fifty-seven thousand, four hundred forty-three".