646000009 has 4 divisors (see below), whose sum is σ = 649382400. Its totient is φ = 642617620.

The previous prime is 646000001. The next prime is 646000049. The reversal of 646000009 is 900000646.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 900000646 = 2 ⋅450000323.

It is a cyclic number.

It is not a de Polignac number, because 646000009 - 2³ = 646000001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646000001) 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, 1690909 + ... + 1691290.

It is an arithmetic number, because the mean of its divisors is an integer number (162345600).

Almost surely, 2^646000009 is an apocalyptic number.

It is an amenable number.

646000009 is a deficient number, since it is larger than the sum of its proper divisors (3382391).

646000009 is a wasteful number, since it uses less digits than its factorization.

646000009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3382390.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 646000009 is about 25416.5302313278. The cubic root of 646000009 is about 864.4585511893.

The spelling of 646000009 in words is "six hundred forty-six million, nine", and thus it is an aban number.