643500234 has 64 divisors (see below), whose sum is σ = 1551473280. Its totient is φ = 196525440.

The previous prime is 643500229. The next prime is 643500239. The reversal of 643500234 is 432005346.

It is an interprime number because it is at equal distance from previous prime (643500229) and next prime (643500239).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 643500198 and 643500207.

It is not an unprimeable number, because it can be changed into a prime (643500239) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 92829 + ... + 99519.

It is an arithmetic number, because the mean of its divisors is an integer number (24241770).

Almost surely, 2^643500234 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643500234, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (775736640).

643500234 is an abundant number, since it is smaller than the sum of its proper divisors (907973046).

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

643500234 is a wasteful number, since it uses less digits than its factorization.

643500234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6852 (or 6846 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 27.

The square root of 643500234 is about 25367.3064001679. The cubic root of 643500234 is about 863.3420675943.

The spelling of 643500234 in words is "six hundred forty-three million, five hundred thousand, two hundred thirty-four".