18021890508 has 24 divisors (see below), whose sum is σ = 42740441520. Its totient is φ = 5908816320.

The previous prime is 18021890449. The next prime is 18021890527. The reversal of 18021890508 is 80509812081.

It is a self number, because there is not a number n which added to its sum of digits gives 18021890508.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12309303 + ... + 12310766.

It is an arithmetic number, because the mean of its divisors is an integer number (1780851730).

Almost surely, 2^18021890508 is an apocalyptic number.

It is an amenable number.

18021890508 is an abundant number, since it is smaller than the sum of its proper divisors (24718551012).

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

18021890508 is a wasteful number, since it uses less digits than its factorization.

18021890508 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24620137 (or 24620135 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 42.

The spelling of 18021890508 in words is "eighteen billion, twenty-one million, eight hundred ninety thousand, five hundred eight".