18688550538 has 16 divisors (see below), whose sum is σ = 42716687040. Its totient is φ = 5339585856.

The previous prime is 18688550509. The next prime is 18688550567. The reversal of 18688550538 is 83505588681.

It is an interprime number because it is at equal distance from previous prime (18688550509) and next prime (18688550567).

It is a super-2 number, since 2×18688550538² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 222482703 + ... + 222482786.

It is an arithmetic number, because the mean of its divisors is an integer number (2669792940).

Almost surely, 2^18688550538 is an apocalyptic number.

18688550538 is an abundant number, since it is smaller than the sum of its proper divisors (24028136502).

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

18688550538 is a wasteful number, since it uses less digits than its factorization.

18688550538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 444965501.

The product of its (nonzero) digits is 9216000, while the sum is 57.

The spelling of 18688550538 in words is "eighteen billion, six hundred eighty-eight million, five hundred fifty thousand, five hundred thirty-eight".