18521045317 has 4 divisors (see below), whose sum is σ = 18521341740. Its totient is φ = 18520748896.

The previous prime is 18521045311. The next prime is 18521045327. The reversal of 18521045317 is 71354012581.

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 7002175041 + 11518870276 = 83679^2 + 107326^2 .

It is a cyclic number.

It is not a de Polignac number, because 18521045317 - 2³¹ = 16373561669 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 (18521045311) 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, 13942 + ... + 192967.

It is an arithmetic number, because the mean of its divisors is an integer number (4630335435).

Almost surely, 2^18521045317 is an apocalyptic number.

It is an amenable number.

18521045317 is a deficient number, since it is larger than the sum of its proper divisors (296423).

18521045317 is an equidigital number, since it uses as much as digits as its factorization.

18521045317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296422.

The product of its (nonzero) digits is 33600, while the sum is 37.

Adding to 18521045317 its reverse (71354012581), we get a palindrome (89875057898).

The spelling of 18521045317 in words is "eighteen billion, five hundred twenty-one million, forty-five thousand, three hundred seventeen".