81389518945 has 8 divisors (see below), whose sum is σ = 111619911744. Its totient is φ = 55809955824.

The previous prime is 81389518867. The next prime is 81389518957. The reversal of 81389518945 is 54981598318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81389518945 - 2¹⁷ = 81389387873 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1162707379 + ... + 1162707448.

It is an arithmetic number, because the mean of its divisors is an integer number (13952488968).

Almost surely, 2^81389518945 is an apocalyptic number.

It is an amenable number.

81389518945 is a deficient number, since it is larger than the sum of its proper divisors (30230392799).

81389518945 is a wasteful number, since it uses less digits than its factorization.

81389518945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2325414839.

The product of its digits is 12441600, while the sum is 61.

The spelling of 81389518945 in words is "eighty-one billion, three hundred eighty-nine million, five hundred eighteen thousand, nine hundred forty-five".