81854175643 has 2 divisors, whose sum is σ = 81854175644. Its totient is φ = 81854175642.

The previous prime is 81854175581. The next prime is 81854175647. The reversal of 81854175643 is 34657145818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81854175643 - 2⁹ = 81854175131 is a prime.

It is not a weakly prime, because it can be changed into another prime (81854175647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40927087821 + 40927087822.

It is an arithmetic number, because the mean of its divisors is an integer number (40927087822).

Almost surely, 2^81854175643 is an apocalyptic number.

81854175643 is a deficient number, since it is larger than the sum of its proper divisors (1).

81854175643 is an equidigital number, since it uses as much as digits as its factorization.

81854175643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3225600, while the sum is 52.

The spelling of 81854175643 in words is "eighty-one billion, eight hundred fifty-four million, one hundred seventy-five thousand, six hundred forty-three".