644424424446 has 128 divisors (see below), whose sum is σ = 1459346803200. Its totient is φ = 188020224000.

The previous prime is 644424424439. The next prime is 644424424477.

It is a happy number.

644424424446 is nontrivially palindromic in base 10.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644424424395 and 644424424404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 66781830 + ... + 66791478.

It is an arithmetic number, because the mean of its divisors is an integer number (11401146900).

Almost surely, 2^644424424446 is an apocalyptic number.

644424424446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 644424424446, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (729673401600).

644424424446 is an abundant number, since it is smaller than the sum of its proper divisors (814922378754).

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

644424424446 is a wasteful number, since it uses less digits than its factorization.

644424424446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10042.

The product of its digits is 9437184, while the sum is 48.

The spelling of 644424424446 in words is "six hundred forty-four billion, four hundred twenty-four million, four hundred twenty-four thousand, four hundred forty-six".