1821116215 has 4 divisors (see below), whose sum is σ = 2185339464. Its totient is φ = 1456892968.

The previous prime is 1821116207. The next prime is 1821116221. The reversal of 1821116215 is 5126111281.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1821116215 - 2³ = 1821116207 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 182111617 + ... + 182111626.

It is an arithmetic number, because the mean of its divisors is an integer number (546334866).

Almost surely, 2^1821116215 is an apocalyptic number.

1821116215 is a deficient number, since it is larger than the sum of its proper divisors (364223249).

1821116215 is an equidigital number, since it uses as much as digits as its factorization.

1821116215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 364223248.

The product of its digits is 960, while the sum is 28.

The square root of 1821116215 is about 42674.5382517491. The cubic root of 1821116215 is about 1221.1786993654.

Adding to 1821116215 its reverse (5126111281), we get a palindrome (6947227496).

The spelling of 1821116215 in words is "one billion, eight hundred twenty-one million, one hundred sixteen thousand, two hundred fifteen".