643211228 has 24 divisors (see below), whose sum is σ = 1240115184. Its totient is φ = 289472000.

The previous prime is 643211221. The next prime is 643211251. The reversal of 643211228 is 822112346.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 643211228.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643211221) 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, 67925 + ... + 76812.

It is an arithmetic number, because the mean of its divisors is an integer number (51671466).

Almost surely, 2^643211228 is an apocalyptic number.

It is an amenable number.

643211228 is a deficient number, since it is larger than the sum of its proper divisors (596903956).

643211228 is a wasteful number, since it uses less digits than its factorization.

643211228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144853 (or 144851 counting only the distinct ones).

The product of its digits is 4608, while the sum is 29.

The square root of 643211228 is about 25361.6093337943. The cubic root of 643211228 is about 863.2128014409.

It can be divided in two parts, 6 and 43211228, that added together give a palindrome (43211234).

The spelling of 643211228 in words is "six hundred forty-three million, two hundred eleven thousand, two hundred twenty-eight".