1866281 has 2 divisors, whose sum is σ = 1866282. Its totient is φ = 1866280.

The previous prime is 1866269. The next prime is 1866283. The reversal of 1866281 is 1826681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1525225 + 341056 = 1235^2 + 584^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1866281 is a prime.

It is a super-2 number, since 2×1866281² = 6966009541922, which contains 22 as substring.

Together with 1866283, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1866283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 933140 + 933141.

It is an arithmetic number, because the mean of its divisors is an integer number (933141).

2^1866281 is an apocalyptic number.

It is an amenable number.

1866281 is a deficient number, since it is larger than the sum of its proper divisors (1).

1866281 is an equidigital number, since it uses as much as digits as its factorization.

1866281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 32.

The square root of 1866281 is about 1366.1189552890. The cubic root of 1866281 is about 123.1191697618.

The spelling of 1866281 in words is "one million, eight hundred sixty-six thousand, two hundred eighty-one".