1664771 has 2 divisors, whose sum is σ = 1664772. Its totient is φ = 1664770.

The previous prime is 1664713. The next prime is 1664797. The reversal of 1664771 is 1774661.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1664771 - 2¹⁰ = 1663747 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1664701) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832385 + 832386.

It is an arithmetic number, because the mean of its divisors is an integer number (832386).

2^1664771 is an apocalyptic number.

1664771 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664771 is an equidigital number, since it uses as much as digits as its factorization.

1664771 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 32.

The square root of 1664771 is about 1290.2600513075. The cubic root of 1664771 is about 118.5181418692.

The spelling of 1664771 in words is "one million, six hundred sixty-four thousand, seven hundred seventy-one".