643217 has 2 divisors, whose sum is σ = 643218. Its totient is φ = 643216.

The previous prime is 643213. The next prime is 643231. The reversal of 643217 is 712346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 614656 + 28561 = 784^2 + 169^2 .

It is a cyclic number.

It is not a de Polignac number, because 643217 - 2² = 643213 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 643192 and 643201.

It is not a weakly prime, because it can be changed into another prime (643213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321608 + 321609.

It is an arithmetic number, because the mean of its divisors is an integer number (321609).

2⁶⁴³²¹⁷ is an apocalyptic number.

It is an amenable number.

643217 is a deficient number, since it is larger than the sum of its proper divisors (1).

643217 is an equidigital number, since it uses as much as digits as its factorization.

643217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 23.

The square root of 643217 is about 802.0081046972. The cubic root of 643217 is about 86.3215383511.

The spelling of 643217 in words is "six hundred forty-three thousand, two hundred seventeen".