81558549584 has 30 divisors (see below), whose sum is σ = 159107427150. Its totient is φ = 40498663168.

The previous prime is 81558549581. The next prime is 81558549593. The reversal of 81558549584 is 48594585518.

It can be written as a sum of positive squares in 3 ways, for example, as 7182400 + 81551367184 = 2680^2 + 285572^2 .

Its product of digits (46080000) is a multiple of the sum of its prime divisors (6000).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81558549581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13941092 + ... + 13946940.

It is an arithmetic number, because the mean of its divisors is an integer number (5303580905).

Almost surely, 2^81558549584 is an apocalyptic number.

It is an amenable number.

81558549584 is a deficient number, since it is larger than the sum of its proper divisors (77548877566).

81558549584 is an frugal number, since it uses more digits than its factorization.

81558549584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11855 (or 6000 counting only the distinct ones).

The product of its digits is 46080000, while the sum is 62.

The spelling of 81558549584 in words is "eighty-one billion, five hundred fifty-eight million, five hundred forty-nine thousand, five hundred eighty-four".