646345421 has 2 divisors, whose sum is σ = 646345422. Its totient is φ = 646345420.

The previous prime is 646345409. The next prime is 646345451. The reversal of 646345421 is 124543646.

646345421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 493328521 + 153016900 = 22211^2 + 12370^2 .

It is a cyclic number.

It is not a de Polignac number, because 646345421 - 2¹⁰ = 646344397 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646345451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323172710 + 323172711.

It is an arithmetic number, because the mean of its divisors is an integer number (323172711).

Almost surely, 2^646345421 is an apocalyptic number.

It is an amenable number.

646345421 is a deficient number, since it is larger than the sum of its proper divisors (1).

646345421 is an equidigital number, since it uses as much as digits as its factorization.

646345421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 35.

The square root of 646345421 is about 25423.3243498957. The cubic root of 646345421 is about 864.6125971903.

The spelling of 646345421 in words is "six hundred forty-six million, three hundred forty-five thousand, four hundred twenty-one".