1666361 has 2 divisors, whose sum is σ = 1666362. Its totient is φ = 1666360.

The previous prime is 1666351. The next prime is 1666387. The reversal of 1666361 is 1636661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1357225 + 309136 = 1165^2 + 556^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666361 - 2⁶ = 1666297 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833180 + 833181.

It is an arithmetic number, because the mean of its divisors is an integer number (833181).

2^1666361 is an apocalyptic number.

It is an amenable number.

1666361 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666361 is an equidigital number, since it uses as much as digits as its factorization.

1666361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 29.

The square root of 1666361 is about 1290.8760591164. The cubic root of 1666361 is about 118.5558615484. Note that the first 3 decimals are identical.

The spelling of 1666361 in words is "one million, six hundred sixty-six thousand, three hundred sixty-one".