2018181821 has 4 divisors (see below), whose sum is σ = 2018482752. Its totient is φ = 2017880892.

The previous prime is 2018181791. The next prime is 2018181829. The reversal of 2018181821 is 1281818102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2018181821 - 2³⁰ = 944439997 is a prime.

It is a super-2 number, since 2×2018181821² = 8146115725229752082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2018181829) 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, 140171 + ... + 153896.

It is an arithmetic number, because the mean of its divisors is an integer number (504620688).

Almost surely, 2^2018181821 is an apocalyptic number.

It is an amenable number.

2018181821 is a deficient number, since it is larger than the sum of its proper divisors (300931).

2018181821 is an equidigital number, since it uses as much as digits as its factorization.

2018181821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300930.

The product of its (nonzero) digits is 2048, while the sum is 32.

The square root of 2018181821 is about 44924.1785790236. The cubic root of 2018181821 is about 1263.7274816157.

Adding to 2018181821 its reverse (1281818102), we get a palindrome (3299999923).

The spelling of 2018181821 in words is "two billion, eighteen million, one hundred eighty-one thousand, eight hundred twenty-one".