81477932184889 has 2 divisors, whose sum is σ = 81477932184890. Its totient is φ = 81477932184888.

The previous prime is 81477932184821. The next prime is 81477932184923. The reversal of 81477932184889 is 98848123977418.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79987354909225 + 1490577275664 = 8943565^2 + 1220892^2 .

It is a cyclic number.

It is not a de Polignac number, because 81477932184889 - 2¹⁵ = 81477932152121 is a prime.

It is not a weakly prime, because it can be changed into another prime (81477932134889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40738966092444 + 40738966092445.

It is an arithmetic number, because the mean of its divisors is an integer number (40738966092445).

Almost surely, 2^{81477932184889} is an apocalyptic number.

It is an amenable number.

81477932184889 is a deficient number, since it is larger than the sum of its proper divisors (1).

81477932184889 is an equidigital number, since it uses as much as digits as its factorization.

81477932184889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1560674304, while the sum is 79.

The spelling of 81477932184889 in words is "eighty-one trillion, four hundred seventy-seven billion, nine hundred thirty-two million, one hundred eighty-four thousand, eight hundred eighty-nine".