81315481554823 has 2 divisors, whose sum is σ = 81315481554824. Its totient is φ = 81315481554822.

The previous prime is 81315481554803. The next prime is 81315481554851. The reversal of 81315481554823 is 32845518451318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81315481554823 - 2¹⁷ = 81315481423751 is a prime.

It is a super-2 number, since 2×81315481554823² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81315481554803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40657740777411 + 40657740777412.

It is an arithmetic number, because the mean of its divisors is an integer number (40657740777412).

Almost surely, 2^{81315481554823} is an apocalyptic number.

81315481554823 is a deficient number, since it is larger than the sum of its proper divisors (1).

81315481554823 is an equidigital number, since it uses as much as digits as its factorization.

81315481554823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18432000, while the sum is 58.

The spelling of 81315481554823 in words is "eighty-one trillion, three hundred fifteen billion, four hundred eighty-one million, five hundred fifty-four thousand, eight hundred twenty-three".