1664569 has 2 divisors, whose sum is σ = 1664570. Its totient is φ = 1664568.

The previous prime is 1664563. The next prime is 1664627. The reversal of 1664569 is 9654661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1658944 + 5625 = 1288^2 + 75^2 .

It is a cyclic number.

It is not a de Polignac number, because 1664569 - 2³ = 1664561 is a prime.

It is a super-2 number, since 2×1664569² = 5541579911522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1664561) 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, 832284 + 832285.

It is an arithmetic number, because the mean of its divisors is an integer number (832285).

2^1664569 is an apocalyptic number.

It is an amenable number.

1664569 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664569 is an equidigital number, since it uses as much as digits as its factorization.

1664569 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 37.

The square root of 1664569 is about 1290.1817701394. The cubic root of 1664569 is about 118.5133480902.

The spelling of 1664569 in words is "one million, six hundred sixty-four thousand, five hundred sixty-nine".