81641874585547 has 2 divisors, whose sum is σ = 81641874585548. Its totient is φ = 81641874585546.

The previous prime is 81641874585539. The next prime is 81641874585679. The reversal of 81641874585547 is 74558547814618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81641874585547 - 2³ = 81641874585539 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81641874585547.

It is not a weakly prime, because it can be changed into another prime (81641874585247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40820937292773 + 40820937292774.

It is an arithmetic number, because the mean of its divisors is an integer number (40820937292774).

Almost surely, 2^{81641874585547} is an apocalyptic number.

81641874585547 is a deficient number, since it is larger than the sum of its proper divisors (1).

81641874585547 is an equidigital number, since it uses as much as digits as its factorization.

81641874585547 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1204224000, while the sum is 73.

The spelling of 81641874585547 in words is "eighty-one trillion, six hundred forty-one billion, eight hundred seventy-four million, five hundred eighty-five thousand, five hundred forty-seven".