1666417 has 2 divisors, whose sum is σ = 1666418. Its totient is φ = 1666416.

The previous prime is 1666409. The next prime is 1666421. The reversal of 1666417 is 7146661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 876096 + 790321 = 936^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666417 - 2³ = 1666409 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833208 + 833209.

It is an arithmetic number, because the mean of its divisors is an integer number (833209).

2^1666417 is an apocalyptic number.

It is an amenable number.

1666417 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666417 is an equidigital number, since it uses as much as digits as its factorization.

1666417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 31.

The square root of 1666417 is about 1290.8977496301. The cubic root of 1666417 is about 118.5571896027.

The spelling of 1666417 in words is "one million, six hundred sixty-six thousand, four hundred seventeen".