643128490 has 16 divisors (see below), whose sum is σ = 1176609960. Its totient is φ = 253033920.

The previous prime is 643128481. The next prime is 643128491. The reversal of 643128490 is 94821346.

643128490 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 381303729 + 261824761 = 19527^2 + 16181^2 .

It is a super-3 number, since 3×643128490³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (643128491) 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, 526545 + ... + 527764.

Almost surely, 2^643128490 is an apocalyptic number.

643128490 is a deficient number, since it is larger than the sum of its proper divisors (533481470).

643128490 is a wasteful number, since it uses less digits than its factorization.

643128490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1054377.

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 643128490 is about 25359.9781151325. The cubic root of 643128490 is about 863.1757873879.

The spelling of 643128490 in words is "six hundred forty-three million, one hundred twenty-eight thousand, four hundred ninety".