643216522 has 16 divisors (see below), whose sum is σ = 1100162952. Its totient is φ = 279406080.

The previous prime is 643216447. The next prime is 643216529. The reversal of 643216522 is 225612346.

It can be written as a sum of positive squares in 4 ways, for example, as 635493681 + 7722841 = 25209^2 + 2779^2 .

It is not an unprimeable number, because it can be changed into a prime (643216529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 727179 + ... + 728062.

Almost surely, 2^643216522 is an apocalyptic number.

643216522 is a deficient number, since it is larger than the sum of its proper divisors (456946430).

643216522 is a wasteful number, since it uses less digits than its factorization.

643216522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1455273.

The product of its digits is 17280, while the sum is 31.

The square root of 643216522 is about 25361.7137039278. The cubic root of 643216522 is about 863.2151696810.

Adding to 643216522 its reverse (225612346), we get a palindrome (868828868).

The spelling of 643216522 in words is "six hundred forty-three million, two hundred sixteen thousand, five hundred twenty-two".