644543345446 has 128 divisors (see below), whose sum is σ = 1378446418944. Its totient is φ = 217535569920.

The previous prime is 644543345431. The next prime is 644543345471.

It is a happy number.

644543345446 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×644543345446² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644543345393 and 644543345402.

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 11782510 + ... + 11837086.

It is an arithmetic number, because the mean of its divisors is an integer number (10769112648).

Almost surely, 2^644543345446 is an apocalyptic number.

644543345446 is an abundant number, since it is smaller than the sum of its proper divisors (733903073498).

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

644543345446 is a wasteful number, since it uses less digits than its factorization.

644543345446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54974.

The product of its digits is 33177600, while the sum is 52.

It can be divided in two parts, 644543 and 345446, that added together give a palindrome (989989).

The spelling of 644543345446 in words is "six hundred forty-four billion, five hundred forty-three million, three hundred forty-five thousand, four hundred forty-six".