18555558121 has 8 divisors (see below), whose sum is σ = 19161062144. Its totient is φ = 17950487760.

The previous prime is 18555558083. The next prime is 18555558167. The reversal of 18555558121 is 12185555581.

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

It is a cyclic number.

It is not a de Polignac number, because 18555558121 - 2¹⁷ = 18555427049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18555558181) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20295 + ... + 193708.

It is an arithmetic number, because the mean of its divisors is an integer number (2395132768).

Almost surely, 2^18555558121 is an apocalyptic number.

It is an amenable number.

18555558121 is a deficient number, since it is larger than the sum of its proper divisors (605504023).

18555558121 is a wasteful number, since it uses less digits than its factorization.

18555558121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216831.

The product of its digits is 400000, while the sum is 46.

The spelling of 18555558121 in words is "eighteen billion, five hundred fifty-five million, five hundred fifty-eight thousand, one hundred twenty-one".