643565213 has 2 divisors, whose sum is σ = 643565214. Its totient is φ = 643565212.

The previous prime is 643565201. The next prime is 643565227. The reversal of 643565213 is 312565346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 547466404 + 96098809 = 23398^2 + 9803^2 .

It is a cyclic number.

It is not a de Polignac number, because 643565213 - 2²² = 639370909 is a prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643561213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321782606 + 321782607.

It is an arithmetic number, because the mean of its divisors is an integer number (321782607).

Almost surely, 2^643565213 is an apocalyptic number.

It is an amenable number.

643565213 is a deficient number, since it is larger than the sum of its proper divisors (1).

643565213 is an equidigital number, since it uses as much as digits as its factorization.

643565213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64800, while the sum is 35.

The square root of 643565213 is about 25368.5871305439. The cubic root of 643565213 is about 863.3711259707.

The spelling of 643565213 in words is "six hundred forty-three million, five hundred sixty-five thousand, two hundred thirteen".