81115108799 has 4 divisors (see below), whose sum is σ = 81125056320. Its totient is φ = 81105161280.

The previous prime is 81115108783. The next prime is 81115108819. The reversal of 81115108799 is 99780151118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81115108799 - 2⁴ = 81115108783 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 (81115108759) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4961519 + ... + 4977840.

It is an arithmetic number, because the mean of its divisors is an integer number (20281264080).

Almost surely, 2^81115108799 is an apocalyptic number.

81115108799 is a deficient number, since it is larger than the sum of its proper divisors (9947521).

81115108799 is an equidigital number, since it uses as much as digits as its factorization.

81115108799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9947520.

The product of its (nonzero) digits is 181440, while the sum is 50.

The spelling of 81115108799 in words is "eighty-one billion, one hundred fifteen million, one hundred eight thousand, seven hundred ninety-nine".