643199616 has 224 divisors, whose sum is σ = 1969957620. Its totient is φ = 209018880.

The previous prime is 643199603. The next prime is 643199621. The reversal of 643199616 is 616991346.

It can be written as a sum of positive squares in 2 ways, for example, as 421070400 + 222129216 = 20520^2 + 14904^2 .

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 5691976 + ... + 5692088.

Almost surely, 2^643199616 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 643199616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (984978810).

643199616 is an abundant number, since it is smaller than the sum of its proper divisors (1326758004).

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

643199616 is an equidigital number, since it uses as much as digits as its factorization.

643199616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206 (or 179 counting only the distinct ones).

The product of its digits is 209952, while the sum is 45.

The square root of 643199616 is about 25361.3804040711. The cubic root of 643199616 is about 863.2076068345.

The spelling of 643199616 in words is "six hundred forty-three million, one hundred ninety-nine thousand, six hundred sixteen".