643481400 has 96 divisors (see below), whose sum is σ = 2024691840. Its totient is φ = 169023360.

The previous prime is 643481381. The next prime is 643481401. The reversal of 643481400 is 4184346.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643481401) 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 23 ways as a sum of consecutive naturals, for example, 32197 + ... + 48203.

It is an arithmetic number, because the mean of its divisors is an integer number (21090540).

Almost surely, 2^643481400 is an apocalyptic number.

643481400 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 643481400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1012345920).

643481400 is an abundant number, since it is smaller than the sum of its proper divisors (1381210440).

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

643481400 is a wasteful number, since it uses less digits than its factorization.

643481400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16093 (or 16084 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 643481400 is about 25366.9351715969. The cubic root of 643481400 is about 863.3336447312. Note that the first 3 decimals are identical.

The spelling of 643481400 in words is "six hundred forty-three million, four hundred eighty-one thousand, four hundred".