18820161 has 16 divisors (see below), whose sum is σ = 28636800. Its totient is φ = 12207024.

The previous prime is 18820129. The next prime is 18820169. The reversal of 18820161 is 16102881.

It is not a de Polignac number, because 18820161 - 2⁵ = 18820129 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (18820169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8421 + ... + 10418.

It is an arithmetic number, because the mean of its divisors is an integer number (1789800).

Almost surely, 2^18820161 is an apocalyptic number.

It is an amenable number.

18820161 is a deficient number, since it is larger than the sum of its proper divisors (9816639).

18820161 is a wasteful number, since it uses less digits than its factorization.

18820161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18885 (or 18879 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 18820161 is about 4338.2209487300. The cubic root of 18820161 is about 265.9955951180.

It can be divided in two parts, 18820 and 161, that added together give a palindrome (18981).

The spelling of 18820161 in words is "eighteen million, eight hundred twenty thousand, one hundred sixty-one".