18943991945 has 8 divisors (see below), whose sum is σ = 23105459400. Its totient is φ = 14906747520.

The previous prime is 18943991923. The next prime is 18943991951. The reversal of 18943991945 is 54919934981.

It can be written as a sum of positive squares in 4 ways, for example, as 1669621321 + 17274370624 = 40861^2 + 131432^2 .

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

It is not a de Polignac number, because 18943991945 - 2²⁴ = 18927214729 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31055420 + ... + 31056029.

It is an arithmetic number, because the mean of its divisors is an integer number (2888182425).

Almost surely, 2^18943991945 is an apocalyptic number.

It is an amenable number.

18943991945 is a deficient number, since it is larger than the sum of its proper divisors (4161467455).

18943991945 is an equidigital number, since it uses as much as digits as its factorization.

18943991945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62111515.

The product of its digits is 12597120, while the sum is 62.

The spelling of 18943991945 in words is "eighteen billion, nine hundred forty-three million, nine hundred ninety-one thousand, nine hundred forty-five".