643055616 has 270 divisors, whose sum is σ = 2185231230. Its totient is φ = 181665792.

The previous prime is 643055593. The next prime is 643055713. The reversal of 643055616 is 616550346.

643055616 is a `hidden beast` number, since 6 + 4 + 30 + 5 + 5 + 616 = 666.

It can be written as a sum of positive squares in only one way, i.e., 462422016 + 180633600 = 21504^2 + 13440^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7225300 + ... + 7225388.

It is an arithmetic number, because the mean of its divisors is an integer number (8093449).

Almost surely, 2^643055616 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 643055616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1092615615).

643055616 is an abundant number, since it is smaller than the sum of its proper divisors (1542175614).

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

643055616 is an equidigital number, since it uses as much as digits as its factorization.

643055616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 643055616 is about 25358.5412829682. The cubic root of 643055616 is about 863.1431835100.

The spelling of 643055616 in words is "six hundred forty-three million, fifty-five thousand, six hundred sixteen".