1827808121 has 4 divisors (see below), whose sum is σ = 1827901812. Its totient is φ = 1827714432.

The previous prime is 1827808111. The next prime is 1827808123. The reversal of 1827808121 is 1218087281.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1218087281 = 17 ⋅71652193.

It can be written as a sum of positive squares in 2 ways, for example, as 543589225 + 1284218896 = 23315^2 + 35836^2 .

It is a cyclic number.

It is not a de Polignac number, because 1827808121 - 2¹⁰ = 1827807097 is a prime.

It is a super-3 number, since 3×1827808121³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1827808123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5300 + ... + 60693.

It is an arithmetic number, because the mean of its divisors is an integer number (456975453).

Almost surely, 2^1827808121 is an apocalyptic number.

It is an amenable number.

1827808121 is a deficient number, since it is larger than the sum of its proper divisors (93691).

1827808121 is an equidigital number, since it uses as much as digits as its factorization.

1827808121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93690.

The product of its (nonzero) digits is 14336, while the sum is 38.

The square root of 1827808121 is about 42752.8726637170. The cubic root of 1827808121 is about 1222.6726592617.

The spelling of 1827808121 in words is "one billion, eight hundred twenty-seven million, eight hundred eight thousand, one hundred twenty-one".