643626900 has 324 divisors, whose sum is σ = 2441947872. Its totient is φ = 138879360.

The previous prime is 643626889. The next prime is 643626901. The reversal of 643626900 is 9626346.

643626900 is a `hidden beast` number, since 643 + 6 + 2 + 6 + 9 + 0 + 0 = 666.

It is a super-2 number, since 2×643626900² = 828511172807220000, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643626901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 2274159 + ... + 2274441.

Almost surely, 2^643626900 is an apocalyptic number.

643626900 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 643626900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1220973936).

643626900 is an abundant number, since it is smaller than the sum of its proper divisors (1798320972).

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

643626900 is a wasteful number, since it uses less digits than its factorization.

643626900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348 (or 319 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 643626900 is about 25369.8029160654. The cubic root of 643626900 is about 863.3987103667.

The spelling of 643626900 in words is "six hundred forty-three million, six hundred twenty-six thousand, nine hundred".