643420400000 has 768 divisors, whose sum is σ = 1949095249920. Its totient is φ = 206807040000.

The previous prime is 643420399907. The next prime is 643420400009. The reversal of 643420400000 is 4024346.

It is a happy number.

It is a super-2 number, since 2×643420400000² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643420400009) 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 95 ways as a sum of consecutive naturals, for example, 6246799949 + ... + 6246800051.

It is an arithmetic number, because the mean of its divisors is an integer number (2537884440).

Almost surely, 2^643420400000 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 643420400000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (974547624960).

643420400000 is an abundant number, since it is smaller than the sum of its proper divisors (1305674849920).

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

643420400000 is an equidigital number, since it uses as much as digits as its factorization.

643420400000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269 (or 237 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 23.

Adding to 643420400000 its reverse (4024346), we get a palindrome (643424424346).

The spelling of 643420400000 in words is "six hundred forty-three billion, four hundred twenty million, four hundred thousand".