643540450 has 192 divisors, whose sum is σ = 1542758400. Its totient is φ = 194745600.

The previous prime is 643540441. The next prime is 643540453. The reversal of 643540450 is 54045346.

It is not an unprimeable number, because it can be changed into a prime (643540453) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9063915 + ... + 9063985.

It is an arithmetic number, because the mean of its divisors is an integer number (8035200).

Almost surely, 2^643540450 is an apocalyptic number.

643540450 is an abundant number, since it is smaller than the sum of its proper divisors (899217950).

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

643540450 is a wasteful number, since it uses less digits than its factorization.

643540450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 31.

The square root of 643540450 is about 25368.0990616167. The cubic root of 643540450 is about 863.3600522764.

Adding to 643540450 its reverse (54045346), we get a palindrome (697585796).

The spelling of 643540450 in words is "six hundred forty-three million, five hundred forty thousand, four hundred fifty".