643075217 has 2 divisors, whose sum is σ = 643075218. Its totient is φ = 643075216.

The previous prime is 643075211. The next prime is 643075219. The reversal of 643075217 is 712570346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 487349776 + 155725441 = 22076^2 + 12479^2 .

It is a cyclic number.

It is not a de Polignac number, because 643075217 - 2¹⁴ = 643058833 is a prime.

Together with 643075219, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (643075211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321537608 + 321537609.

It is an arithmetic number, because the mean of its divisors is an integer number (321537609).

Almost surely, 2^643075217 is an apocalyptic number.

It is an amenable number.

643075217 is a deficient number, since it is larger than the sum of its proper divisors (1).

643075217 is an equidigital number, since it uses as much as digits as its factorization.

643075217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35280, while the sum is 35.

The square root of 643075217 is about 25358.9277573008. The cubic root of 643075217 is about 863.1519532531.

The spelling of 643075217 in words is "six hundred forty-three million, seventy-five thousand, two hundred seventeen".