81009793805 has 16 divisors (see below), whose sum is σ = 100400767488. Its totient is φ = 62684040000.

The previous prime is 81009793801. The next prime is 81009793817. The reversal of 81009793805 is 50839790018.

It is not a de Polignac number, because 81009793805 - 2² = 81009793801 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81009793801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157190 + ... + 432120.

It is an arithmetic number, because the mean of its divisors is an integer number (6275047968).

Almost surely, 2^81009793805 is an apocalyptic number.

It is an amenable number.

81009793805 is a deficient number, since it is larger than the sum of its proper divisors (19390973683).

81009793805 is a wasteful number, since it uses less digits than its factorization.

81009793805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276868.

The product of its (nonzero) digits is 544320, while the sum is 50.

The spelling of 81009793805 in words is "eighty-one billion, nine million, seven hundred ninety-three thousand, eight hundred five".