643421026 has 4 divisors (see below), whose sum is σ = 965131542. Its totient is φ = 321710512.

The previous prime is 643421003. The next prime is 643421029. The reversal of 643421026 is 620124346.

643421026 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 620124346 = 2 ⋅310062173.

It can be written as a sum of positive squares in only one way, i.e., 357777225 + 285643801 = 18915^2 + 16901^2 .

It is a junction number, because it is equal to n+sod(n) for n = 643420985 and 643421003.

It is not an unprimeable number, because it can be changed into a prime (643421029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160855255 + ... + 160855258.

Almost surely, 2^643421026 is an apocalyptic number.

643421026 is a deficient number, since it is larger than the sum of its proper divisors (321710516).

643421026 is a wasteful number, since it uses less digits than its factorization.

643421026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321710515.

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 643421026 is about 25365.7451299977. The cubic root of 643421026 is about 863.3066434143.

The spelling of 643421026 in words is "six hundred forty-three million, four hundred twenty-one thousand, twenty-six".