18515316987 has 8 divisors (see below), whose sum is σ = 27430099280. Its totient is φ = 12343544640.

The previous prime is 18515316983. The next prime is 18515317031. The reversal of 18515316987 is 78961351581.

It is a happy number.

18515316987 is a `hidden beast` number, since 1 + 8 + 515 + 31 + 6 + 98 + 7 = 666.

It is not a de Polignac number, because 18515316987 - 2² = 18515316983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18515316983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 342876214 + ... + 342876267.

It is an arithmetic number, because the mean of its divisors is an integer number (3428762410).

Almost surely, 2^18515316987 is an apocalyptic number.

18515316987 is a deficient number, since it is larger than the sum of its proper divisors (8914782293).

18515316987 is an equidigital number, since it uses as much as digits as its factorization.

18515316987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 685752490 (or 685752484 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 54.

Adding to 18515316987 its sum of digits (54), we get a square (18515317041 = 136071²).

The spelling of 18515316987 in words is "eighteen billion, five hundred fifteen million, three hundred sixteen thousand, nine hundred eighty-seven".