643340622440 has 64 divisors (see below), whose sum is σ = 1527946416000. Its totient is φ = 243113045760.

The previous prime is 643340622437. The next prime is 643340622443. The reversal of 643340622440 is 44226043346.

It is an interprime number because it is at equal distance from previous prime (643340622437) and next prime (643340622443).

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a junction number, because it is equal to n+sod(n) for n = 643340622394 and 643340622403.

It is not an unprimeable number, because it can be changed into a prime (643340622443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 906131 + ... + 1451810.

It is an arithmetic number, because the mean of its divisors is an integer number (23874162750).

Almost surely, 2^643340622440 is an apocalyptic number.

It is an amenable number.

643340622440 is an abundant number, since it is smaller than the sum of its proper divisors (884605793560).

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

643340622440 is a wasteful number, since it uses less digits than its factorization.

643340622440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2358330 (or 2358326 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 38.

Adding to 643340622440 its reverse (44226043346), we get a palindrome (687566665786).

The spelling of 643340622440 in words is "six hundred forty-three billion, three hundred forty million, six hundred twenty-two thousand, four hundred forty".