643687200 has 486 divisors, whose sum is σ = 2569341411. Its totient is φ = 151557120.

The previous prime is 643687147. The next prime is 643687217. The reversal of 643687200 is 2786346.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

643687200 is a `hidden beast` number, since 643 + 6 + 8 + 7 + 2 + 0 + 0 = 666.

It can be written as a sum of positive squares in 5 ways, for example, as 40297104 + 603390096 = 6348^2 + 24564^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=17940.

It is a super-2 number, since 2×643687200² = 828666422887680000, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 27986389 + ... + 27986411.

Almost surely, 2^643687200 is an apocalyptic number.

643687200 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643687200

643687200 is an abundant number, since it is smaller than the sum of its proper divisors (1925654211).

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

643687200 is a wasteful number, since it uses less digits than its factorization.

643687200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 643687200 is about 25370.9913089733. The cubic root of 643687200 is about 863.4256728386.

It can be divided in two parts, 6436 and 87200, that added together give a square (93636 = 306²).

The spelling of 643687200 in words is "six hundred forty-three million, six hundred eighty-seven thousand, two hundred".