643466917 has 2 divisors, whose sum is σ = 643466918. Its totient is φ = 643466916.

The previous prime is 643466903. The next prime is 643466927. The reversal of 643466917 is 719664346.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 642825316 + 641601 = 25354^2 + 801^2 .

It is a cyclic number.

It is not a de Polignac number, because 643466917 - 2¹⁵ = 643434149 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643466927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321733458 + 321733459.

It is an arithmetic number, because the mean of its divisors is an integer number (321733459).

Almost surely, 2^643466917 is an apocalyptic number.

It is an amenable number.

643466917 is a deficient number, since it is larger than the sum of its proper divisors (1).

643466917 is an equidigital number, since it uses as much as digits as its factorization.

643466917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 46.

The square root of 643466917 is about 25366.6496999505. The cubic root of 643466917 is about 863.3271675924.

The spelling of 643466917 in words is "six hundred forty-three million, four hundred sixty-six thousand, nine hundred seventeen".