81231193085 has 8 divisors (see below), whose sum is σ = 111402779136. Its totient is φ = 55701389520.

The previous prime is 81231193061. The next prime is 81231193111. The reversal of 81231193085 is 58039113218.

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

It is not a de Polignac number, because 81231193085 - 2²⁴ = 81214415869 is a prime.

It is a Duffinian number.

It is a congruent 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, 1160445581 + ... + 1160445650.

It is an arithmetic number, because the mean of its divisors is an integer number (13925347392).

Almost surely, 2^81231193085 is an apocalyptic number.

It is an amenable number.

81231193085 is a deficient number, since it is larger than the sum of its proper divisors (30171586051).

81231193085 is a wasteful number, since it uses less digits than its factorization.

81231193085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2320891243.

The product of its (nonzero) digits is 51840, while the sum is 41.

The spelling of 81231193085 in words is "eighty-one billion, two hundred thirty-one million, one hundred ninety-three thousand, eighty-five".