81074100109 has 4 divisors (see below), whose sum is σ = 81075069180. Its totient is φ = 81073131040.

The previous prime is 81074100097. The next prime is 81074100113. The reversal of 81074100109 is 90100147018.

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

It can be written as a sum of positive squares in 2 ways, for example, as 71397443209 + 9676656900 = 267203^2 + 98370^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81074100109 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 (81074100409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 345802 + ... + 530779.

It is an arithmetic number, because the mean of its divisors is an integer number (20268767295).

Almost surely, 2^81074100109 is an apocalyptic number.

It is an amenable number.

81074100109 is a deficient number, since it is larger than the sum of its proper divisors (969071).

81074100109 is an equidigital number, since it uses as much as digits as its factorization.

81074100109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 969070.

The product of its (nonzero) digits is 2016, while the sum is 31.

The spelling of 81074100109 in words is "eighty-one billion, seventy-four million, one hundred thousand, one hundred nine".