646973609 has 2 divisors, whose sum is σ = 646973610. Its totient is φ = 646973608.

The previous prime is 646973603. The next prime is 646973623. The reversal of 646973609 is 906379646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 622003600 + 24970009 = 24940^2 + 4997^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646973609 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (646973603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323486804 + 323486805.

It is an arithmetic number, because the mean of its divisors is an integer number (323486805).

Almost surely, 2^646973609 is an apocalyptic number.

It is an amenable number.

646973609 is a deficient number, since it is larger than the sum of its proper divisors (1).

646973609 is an equidigital number, since it uses as much as digits as its factorization.

646973609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1469664, while the sum is 50.

The square root of 646973609 is about 25435.6759100284. The cubic root of 646973609 is about 864.8926143324.

The spelling of 646973609 in words is "six hundred forty-six million, nine hundred seventy-three thousand, six hundred nine".