646896389 has 2 divisors, whose sum is σ = 646896390. Its totient is φ = 646896388.

The previous prime is 646896373. The next prime is 646896431. The reversal of 646896389 is 983698646.

646896389 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., 619512100 + 27384289 = 24890^2 + 5233^2 .

It is a cyclic number.

It is not a de Polignac number, because 646896389 - 2⁴ = 646896373 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 (646896989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323448194 + 323448195.

It is an arithmetic number, because the mean of its divisors is an integer number (323448195).

Almost surely, 2^646896389 is an apocalyptic number.

It is an amenable number.

646896389 is a deficient number, since it is larger than the sum of its proper divisors (1).

646896389 is an equidigital number, since it uses as much as digits as its factorization.

646896389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13436928, while the sum is 59.

The square root of 646896389 is about 25434.1579180440. The cubic root of 646896389 is about 864.8582030035.

The spelling of 646896389 in words is "six hundred forty-six million, eight hundred ninety-six thousand, three hundred eighty-nine".