643268489 has 2 divisors, whose sum is σ = 643268490. Its totient is φ = 643268488.

The previous prime is 643268477. The next prime is 643268537. The reversal of 643268489 is 984862346.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 604766464 + 38502025 = 24592^2 + 6205^2 .

It is a cyclic number.

It is not a de Polignac number, because 643268489 - 2⁸ = 643268233 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (643267489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321634244 + 321634245.

It is an arithmetic number, because the mean of its divisors is an integer number (321634245).

Almost surely, 2^643268489 is an apocalyptic number.

It is an amenable number.

643268489 is a deficient number, since it is larger than the sum of its proper divisors (1).

643268489 is an equidigital number, since it uses as much as digits as its factorization.

643268489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1990656, while the sum is 50.

The square root of 643268489 is about 25362.7381999657. The cubic root of 643268489 is about 863.2384161272.

The spelling of 643268489 in words is "six hundred forty-three million, two hundred sixty-eight thousand, four hundred eighty-nine".