18805121 has 4 divisors (see below), whose sum is σ = 18971652. Its totient is φ = 18638592.

The previous prime is 18805109. The next prime is 18805133. The reversal of 18805121 is 12150881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12150881 = 1093 ⋅11117.

It is an interprime number because it is at equal distance from previous prime (18805109) and next prime (18805133).

It can be written as a sum of positive squares in 2 ways, for example, as 409600 + 18395521 = 640^2 + 4289^2 .

It is a cyclic number.

It is not a de Polignac number, because 18805121 - 2⁶ = 18805057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18805321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83096 + ... + 83321.

It is an arithmetic number, because the mean of its divisors is an integer number (4742913).

Almost surely, 2^18805121 is an apocalyptic number.

It is an amenable number.

18805121 is a deficient number, since it is larger than the sum of its proper divisors (166531).

18805121 is a wasteful number, since it uses less digits than its factorization.

18805121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166530.

The product of its (nonzero) digits is 640, while the sum is 26.

The square root of 18805121 is about 4336.4871728163. The cubic root of 18805121 is about 265.9247200619.

The spelling of 18805121 in words is "eighteen million, eight hundred five thousand, one hundred twenty-one".