643396494400 has 189 divisors, whose sum is σ = 1741119939013. Its totient is φ = 233834022400.

The previous prime is 643396494379. The next prime is 643396494401. The reversal of 643396494400 is 4494693346.

The square root of 643396494400 is 802120.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 231622737984 + 411773756416 = 481272^2 + 641696^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643396494401) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 352931889 + ... + 352933711.

Almost surely, 2^643396494400 is an apocalyptic number.

643396494400 is the 802120-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643396494400

643396494400 is an abundant number, since it is smaller than the sum of its proper divisors (1097723444613).

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

643396494400 is an equidigital number, since it uses as much as digits as its factorization.

643396494400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3690 (or 1841 counting only the distinct ones).

The product of its (nonzero) digits is 6718464, while the sum is 52.

The spelling of 643396494400 in words is "six hundred forty-three billion, three hundred ninety-six million, four hundred ninety-four thousand, four hundred".