18911209145 has 8 divisors (see below), whose sum is σ = 22727174856. Its totient is φ = 15106484736.

The previous prime is 18911209103. The next prime is 18911209147. The reversal of 18911209145 is 54190211981.

It can be written as a sum of positive squares in 4 ways, for example, as 3690805504 + 15220403641 = 60752^2 + 123371^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 18911209145 - 2¹⁴ = 18911192761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18911209147) 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 7 ways as a sum of consecutive naturals, for example, 2806622 + ... + 2813351.

It is an arithmetic number, because the mean of its divisors is an integer number (2840896857).

Almost surely, 2^18911209145 is an apocalyptic number.

It is an amenable number.

18911209145 is a deficient number, since it is larger than the sum of its proper divisors (3815965711).

18911209145 is an equidigital number, since it uses as much as digits as its factorization.

18911209145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5620651.

The product of its (nonzero) digits is 25920, while the sum is 41.

The spelling of 18911209145 in words is "eighteen billion, nine hundred eleven million, two hundred nine thousand, one hundred forty-five".