81505583194223 has 2 divisors, whose sum is σ = 81505583194224. Its totient is φ = 81505583194222.

The previous prime is 81505583194207. The next prime is 81505583194229. The reversal of 81505583194223 is 32249138550518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81505583194223 - 2⁴ = 81505583194207 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81505583194229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40752791597111 + 40752791597112.

It is an arithmetic number, because the mean of its divisors is an integer number (40752791597112).

Almost surely, 2^{81505583194223} is an apocalyptic number.

81505583194223 is a deficient number, since it is larger than the sum of its proper divisors (1).

81505583194223 is an equidigital number, since it uses as much as digits as its factorization.

81505583194223 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368000, while the sum is 56.

The spelling of 81505583194223 in words is "eighty-one trillion, five hundred five billion, five hundred eighty-three million, one hundred ninety-four thousand, two hundred twenty-three".