643602389 has 2 divisors, whose sum is σ = 643602390. Its totient is φ = 643602388.

The previous prime is 643602367. The next prime is 643602391. The reversal of 643602389 is 983206346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 363207364 + 280395025 = 19058^2 + 16745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643602389 is a prime.

Together with 643602391, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643602319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321801194 + 321801195.

It is an arithmetic number, because the mean of its divisors is an integer number (321801195).

Almost surely, 2^643602389 is an apocalyptic number.

It is an amenable number.

643602389 is a deficient number, since it is larger than the sum of its proper divisors (1).

643602389 is an equidigital number, since it uses as much as digits as its factorization.

643602389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 41.

The square root of 643602389 is about 25369.3198371576. The cubic root of 643602389 is about 863.3877500653.

The spelling of 643602389 in words is "six hundred forty-three million, six hundred two thousand, three hundred eighty-nine".