644464181464446 has 64 divisors (see below), whose sum is σ = 1552325998611456. Its totient is φ = 174383026752000.

The previous prime is 644464181464427. The next prime is 644464181464457.

It is a happy number.

644464181464446 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3302611275 + ... + 3302806406.

It is an arithmetic number, because the mean of its divisors is an integer number (24255093728304).

Almost surely, 2^{644464181464446} is an apocalyptic number.

644464181464446 is an abundant number, since it is smaller than the sum of its proper divisors (907861817147010).

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

644464181464446 is a wasteful number, since it uses less digits than its factorization.

644464181464446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6605417817.

The product of its digits is 679477248, while the sum is 66.

The spelling of 644464181464446 in words is "six hundred forty-four trillion, four hundred sixty-four billion, one hundred eighty-one million, four hundred sixty-four thousand, four hundred forty-six".