643453650 has 144 divisors (see below), whose sum is σ = 1984694400. Its totient is φ = 146407680.

The previous prime is 643453607. The next prime is 643453651. The reversal of 643453650 is 56354346.

643453650 is a `hidden beast` number, since 643 + 4 + 5 + 3 + 6 + 5 + 0 = 666.

It is not an unprimeable number, because it can be changed into a prime (643453651) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1130566 + ... + 1131134.

It is an arithmetic number, because the mean of its divisors is an integer number (13782600).

Almost surely, 2^643453650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643453650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (992347200).

643453650 is an abundant number, since it is smaller than the sum of its proper divisors (1341240750).

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

643453650 is a wasteful number, since it uses less digits than its factorization.

643453650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 953 (or 945 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 36.

The square root of 643453650 is about 25366.3881938285. The cubic root of 643453650 is about 863.3212341922.

The spelling of 643453650 in words is "six hundred forty-three million, four hundred fifty-three thousand, six hundred fifty".