1628609 has 4 divisors (see below), whose sum is σ = 1635204. Its totient is φ = 1622016.

The previous prime is 1628603. The next prime is 1628621. The reversal of 1628609 is 9068261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9068261 = 599 ⋅15139.

It can be written as a sum of positive squares in 2 ways, for example, as 1210000 + 418609 = 1100^2 + 647^2 .

It is a cyclic number.

It is not a de Polignac number, because 1628609 - 2⁴ = 1628593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1628603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2912 + ... + 3425.

It is an arithmetic number, because the mean of its divisors is an integer number (408801).

2^1628609 is an apocalyptic number.

It is an amenable number.

1628609 is a deficient number, since it is larger than the sum of its proper divisors (6595).

1628609 is an equidigital number, since it uses as much as digits as its factorization.

1628609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6594.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 1628609 is about 1276.1696595673. The cubic root of 1628609 is about 117.6537055902.

The spelling of 1628609 in words is "one million, six hundred twenty-eight thousand, six hundred nine".