20187018517 has 4 divisors (see below), whose sum is σ = 20188085536. Its totient is φ = 20185951500.

The previous prime is 20187018497. The next prime is 20187018529. The reversal of 20187018517 is 71581078102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20187018517 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20187018517.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20187058517) 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 3 ways as a sum of consecutive naturals, for example, 504609 + ... + 543142.

It is an arithmetic number, because the mean of its divisors is an integer number (5047021384).

Almost surely, 2^20187018517 is an apocalyptic number.

It is an amenable number.

20187018517 is a deficient number, since it is larger than the sum of its proper divisors (1067019).

20187018517 is a wasteful number, since it uses less digits than its factorization.

20187018517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1067018.

The product of its (nonzero) digits is 31360, while the sum is 40.

The spelling of 20187018517 in words is "twenty billion, one hundred eighty-seven million, eighteen thousand, five hundred seventeen".