18213543709 has 4 divisors (see below), whose sum is σ = 18232187004. Its totient is φ = 18194900416.

The previous prime is 18213543703. The next prime is 18213543713. The reversal of 18213543709 is 90734531281.

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 7362154809 + 10851388900 = 85803^2 + 104170^2 .

It is a cyclic number.

It is not a de Polignac number, because 18213543709 - 2¹⁹ = 18213019421 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 (18213543703) 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, 9320182 + ... + 9322135.

It is an arithmetic number, because the mean of its divisors is an integer number (4558046751).

Almost surely, 2^18213543709 is an apocalyptic number.

It is an amenable number.

18213543709 is a deficient number, since it is larger than the sum of its proper divisors (18643295).

18213543709 is an equidigital number, since it uses as much as digits as its factorization.

18213543709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18643294.

The product of its (nonzero) digits is 181440, while the sum is 43.

The spelling of 18213543709 in words is "eighteen billion, two hundred thirteen million, five hundred forty-three thousand, seven hundred nine".