643616423 has 2 divisors, whose sum is σ = 643616424. Its totient is φ = 643616422.

The previous prime is 643616419. The next prime is 643616461. The reversal of 643616423 is 324616346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643616423 - 2² = 643616419 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643616023) 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, 321808211 + 321808212.

It is an arithmetic number, because the mean of its divisors is an integer number (321808212).

Almost surely, 2^643616423 is an apocalyptic number.

643616423 is a deficient number, since it is larger than the sum of its proper divisors (1).

643616423 is an equidigital number, since it uses as much as digits as its factorization.

643616423 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 35.

The square root of 643616423 is about 25369.5964295848. The cubic root of 643616423 is about 863.3940255214.

The spelling of 643616423 in words is "six hundred forty-three million, six hundred sixteen thousand, four hundred twenty-three".