81580239601 has 6 divisors (see below), whose sum is σ = 94899462450. Its totient is φ = 69925919616.

The previous prime is 81580239577. The next prime is 81580239673. The reversal of 81580239601 is 10693208518.

It can be written as a sum of positive squares in only one way, i.e., 81439461376 + 140778225 = 285376^2 + 11865^2 .

It is not a de Polignac number, because 81580239601 - 2⁷ = 81580239473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81580239001) 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 in 5 ways as a sum of consecutive naturals, for example, 832451376 + ... + 832451473.

It is an arithmetic number, because the mean of its divisors is an integer number (15816577075).

Almost surely, 2^81580239601 is an apocalyptic number.

It is an amenable number.

81580239601 is a deficient number, since it is larger than the sum of its proper divisors (13319222849).

81580239601 is a wasteful number, since it uses less digits than its factorization.

81580239601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1664902863 (or 1664902856 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 43.

The spelling of 81580239601 in words is "eighty-one billion, five hundred eighty million, two hundred thirty-nine thousand, six hundred one".