1663609 has 2 divisors, whose sum is σ = 1663610. Its totient is φ = 1663608.

The previous prime is 1663589. The next prime is 1663619. The reversal of 1663609 is 9063661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1525225 + 138384 = 1235^2 + 372^2 .

It is an emirp because it is prime and its reverse (9063661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1663609 - 2⁷ = 1663481 is a prime.

1663609 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1663619) 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, 831804 + 831805.

It is an arithmetic number, because the mean of its divisors is an integer number (831805).

2^1663609 is an apocalyptic number.

It is an amenable number.

1663609 is a deficient number, since it is larger than the sum of its proper divisors (1).

1663609 is an equidigital number, since it uses as much as digits as its factorization.

1663609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 1663609 is about 1289.8096758825. The cubic root of 1663609 is about 118.4905604711.

The spelling of 1663609 in words is "one million, six hundred sixty-three thousand, six hundred nine".