18018018921 has 32 divisors (see below), whose sum is σ = 29042288640. Its totient is φ = 9713430144.

The previous prime is 18018018901. The next prime is 18018018937. The reversal of 18018018921 is 12981081081.

It is not a de Polignac number, because 18018018921 - 2⁶ = 18018018857 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18018018921.

It is not an unprimeable number, because it can be changed into a prime (18018018901) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 220251 + ... + 290768.

It is an arithmetic number, because the mean of its divisors is an integer number (907571520).

Almost surely, 2^18018018921 is an apocalyptic number.

It is an amenable number.

18018018921 is a deficient number, since it is larger than the sum of its proper divisors (11024269719).

18018018921 is a wasteful number, since it uses less digits than its factorization.

18018018921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511125.

The product of its (nonzero) digits is 9216, while the sum is 39.

The spelling of 18018018921 in words is "eighteen billion, eighteen million, eighteen thousand, nine hundred twenty-one".