18721537518 has 8 divisors (see below), whose sum is σ = 37443075048. Its totient is φ = 6240512504.

The previous prime is 18721537489. The next prime is 18721537553. The reversal of 18721537518 is 81573512781.

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

18721537518 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1560128121 + ... + 1560128132.

It is an arithmetic number, because the mean of its divisors is an integer number (4680384381).

Almost surely, 2^18721537518 is an apocalyptic number.

18721537518 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18721537518 is a wasteful number, since it uses less digits than its factorization.

18721537518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3120256258.

The product of its digits is 470400, while the sum is 48.

The spelling of 18721537518 in words is "eighteen billion, seven hundred twenty-one million, five hundred thirty-seven thousand, five hundred eighteen".