643489128 has 48 divisors (see below), whose sum is σ = 1764859200. Its totient is φ = 211779360.

The previous prime is 643489081. The next prime is 643489129. The reversal of 643489128 is 821984346.

It is a happy number.

643489128 is a `hidden beast` number, since 6 + 43 + 489 + 128 = 666.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (643489129) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 50878 + ... + 62253.

It is an arithmetic number, because the mean of its divisors is an integer number (36767900).

Almost surely, 2^643489128 is an apocalyptic number.

It is an amenable number.

643489128 is an abundant number, since it is smaller than the sum of its proper divisors (1121370072).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643489128 is a wasteful number, since it uses less digits than its factorization.

643489128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113222 (or 113215 counting only the distinct ones).

The product of its digits is 331776, while the sum is 45.

The square root of 643489128 is about 25367.0874954142. The cubic root of 643489128 is about 863.3371008351.

The spelling of 643489128 in words is "six hundred forty-three million, four hundred eighty-nine thousand, one hundred twenty-eight".