1820281 has 2 divisors, whose sum is σ = 1820282. Its totient is φ = 1820280.

The previous prime is 1820279. The next prime is 1820293.

1820281 is nontrivially palindromic in base 10.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1301881 + 518400 = 1141^2 + 720^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 1820281 - 2¹ = 1820279 is a prime.

It is a super-2 number, since 2×1820281² = 6626845837922, which contains 22 as substring.

Together with 1820279, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1820201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910140 + 910141.

It is an arithmetic number, because the mean of its divisors is an integer number (910141).

2^1820281 is an apocalyptic number.

It is an amenable number.

1820281 is a deficient number, since it is larger than the sum of its proper divisors (1).

1820281 is an equidigital number, since it uses as much as digits as its factorization.

1820281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 1820281 is about 1349.1778978326. The cubic root of 1820281 is about 122.0991981878.

The spelling of 1820281 in words is "one million, eight hundred twenty thousand, two hundred eighty-one".