643450028 has 24 divisors (see below), whose sum is σ = 1254474480. Its totient is φ = 286735680.

The previous prime is 643450007. The next prime is 643450033. The reversal of 643450028 is 820054346.

It is a junction number, because it is equal to n+sod(n) for n = 643449976 and 643450003.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 211838 + ... + 214853.

It is an arithmetic number, because the mean of its divisors is an integer number (52269770).

Almost surely, 2^643450028 is an apocalyptic number.

It is an amenable number.

643450028 is a deficient number, since it is larger than the sum of its proper divisors (611024452).

643450028 is a wasteful number, since it uses less digits than its factorization.

643450028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426737 (or 426735 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

The square root of 643450028 is about 25366.3168000402. The cubic root of 643450028 is about 863.3196143110.

The spelling of 643450028 in words is "six hundred forty-three million, four hundred fifty thousand, twenty-eight".