81548056913 has 2 divisors, whose sum is σ = 81548056914. Its totient is φ = 81548056912.

The previous prime is 81548056903. The next prime is 81548056957. The reversal of 81548056913 is 31965084518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55636072129 + 25911984784 = 235873^2 + 160972^2 .

It is a cyclic number.

It is not a de Polignac number, because 81548056913 - 2⁸ = 81548056657 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (81548056903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40774028456 + 40774028457.

It is an arithmetic number, because the mean of its divisors is an integer number (40774028457).

Almost surely, 2^81548056913 is an apocalyptic number.

It is an amenable number.

81548056913 is a deficient number, since it is larger than the sum of its proper divisors (1).

81548056913 is an equidigital number, since it uses as much as digits as its factorization.

81548056913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1036800, while the sum is 50.

The spelling of 81548056913 in words is "eighty-one billion, five hundred forty-eight million, fifty-six thousand, nine hundred thirteen".