1645009 has 2 divisors, whose sum is σ = 1645010. Its totient is φ = 1645008.

The previous prime is 1645003. The next prime is 1645019. The reversal of 1645009 is 9005461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1555009 + 90000 = 1247^2 + 300^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645009 - 2⁹ = 1644497 is a prime.

It is a super-2 number, since 2×1645009² = 5412109220162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1645003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822504 + 822505.

It is an arithmetic number, because the mean of its divisors is an integer number (822505).

2^1645009 is an apocalyptic number.

It is an amenable number.

1645009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645009 is an equidigital number, since it uses as much as digits as its factorization.

1645009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 1645009 is about 1282.5790423986. The cubic root of 1645009 is about 118.0473093838.

Adding to 1645009 its product of nonzero digits (1080), we get a square (1646089 = 1283²).

The spelling of 1645009 in words is "one million, six hundred forty-five thousand, nine".