1820328889 has 4 divisors (see below), whose sum is σ = 1820675556. Its totient is φ = 1819982224.

The previous prime is 1820328871. The next prime is 1820328893. The reversal of 1820328889 is 9888230281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9888230281 = 109 ⋅90717709.

It can be written as a sum of positive squares in 2 ways, for example, as 1804805289 + 15523600 = 42483^2 + 3940^2 .

It is a cyclic number.

It is not a de Polignac number, because 1820328889 - 2¹¹ = 1820326841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1820328899) 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, 165334 + ... + 175999.

It is an arithmetic number, because the mean of its divisors is an integer number (455168889).

Almost surely, 2^1820328889 is an apocalyptic number.

It is an amenable number.

1820328889 is a deficient number, since it is larger than the sum of its proper divisors (346667).

1820328889 is an equidigital number, since it uses as much as digits as its factorization.

1820328889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346666.

The product of its (nonzero) digits is 442368, while the sum is 49.

The square root of 1820328889 is about 42665.3124798120. The cubic root of 1820328889 is about 1221.0026893039.

The spelling of 1820328889 in words is "one billion, eight hundred twenty million, three hundred twenty-eight thousand, eight hundred eighty-nine".