643450212440 has 128 divisors (see below), whose sum is σ = 1712069913600. Its totient is φ = 212950832640.

The previous prime is 643450212437. The next prime is 643450212451. The reversal of 643450212440 is 44212054346.

It is a super-2 number, since 2×643450212440² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 643450212440.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 44904557 + ... + 44918883.

It is an arithmetic number, because the mean of its divisors is an integer number (13375546200).

Almost surely, 2^643450212440 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 643450212440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (856034956800).

643450212440 is an abundant number, since it is smaller than the sum of its proper divisors (1068619701160).

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

643450212440 is a wasteful number, since it uses less digits than its factorization.

643450212440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19905 (or 19901 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 35.

Adding to 643450212440 its reverse (44212054346), we get a palindrome (687662266786).

The spelling of 643450212440 in words is "six hundred forty-three billion, four hundred fifty million, two hundred twelve thousand, four hundred forty".