18643312645 has 8 divisors (see below), whose sum is σ = 22384407960. Its totient is φ = 14906361600.

The previous prime is 18643312643. The next prime is 18643312691. The reversal of 18643312645 is 54621334681.

It can be written as a sum of positive squares in 4 ways, for example, as 1023936001 + 17619376644 = 31999^2 + 132738^2 .

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

It is not a de Polignac number, because 18643312645 - 2¹ = 18643312643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18643312643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1026160 + ... + 1044169.

It is an arithmetic number, because the mean of its divisors is an integer number (2798050995).

Almost surely, 2^18643312645 is an apocalyptic number.

It is an amenable number.

18643312645 is a deficient number, since it is larger than the sum of its proper divisors (3741095315).

18643312645 is a wasteful number, since it uses less digits than its factorization.

18643312645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2072135.

The product of its digits is 414720, while the sum is 43.

The spelling of 18643312645 in words is "eighteen billion, six hundred forty-three million, three hundred twelve thousand, six hundred forty-five".