643496028 has 144 divisors (see below), whose sum is σ = 1853913600. Its totient is φ = 172730880.

The previous prime is 643496027. The next prime is 643496033. The reversal of 643496028 is 820694346.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643496027) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2669988 + ... + 2670228.

It is an arithmetic number, because the mean of its divisors is an integer number (12874400).

Almost surely, 2^643496028 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643496028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (926956800).

643496028 is an abundant number, since it is smaller than the sum of its proper divisors (1210417572).

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

643496028 is a wasteful number, since it uses less digits than its factorization.

643496028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520 (or 511 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 42.

The square root of 643496028 is about 25367.2234980496. The cubic root of 643496028 is about 863.3401866188.

The spelling of 643496028 in words is "six hundred forty-three million, four hundred ninety-six thousand, twenty-eight".