643126346320 has 20 divisors (see below), whose sum is σ = 1495268755380. Its totient is φ = 257250538496.

The previous prime is 643126346293. The next prime is 643126346323. The reversal of 643126346320 is 23643621346.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 481846999104 + 161279347216 = 694152^2 + 401596^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×643126346320² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643126346323) 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 3 ways as a sum of consecutive naturals, for example, 4019539585 + ... + 4019539744.

It is an arithmetic number, because the mean of its divisors is an integer number (74763437769).

Almost surely, 2^643126346320 is an apocalyptic number.

It is an amenable number.

643126346320 is an abundant number, since it is smaller than the sum of its proper divisors (852142409060).

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

643126346320 is a wasteful number, since it uses less digits than its factorization.

643126346320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8039079342 (or 8039079336 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 40.

Adding to 643126346320 its reverse (23643621346), we get a palindrome (666769967666).

The spelling of 643126346320 in words is "six hundred forty-three billion, one hundred twenty-six million, three hundred forty-six thousand, three hundred twenty".