644663323366446 has 128 divisors (see below), whose sum is σ = 1407739894387200. Its totient is φ = 196104527193600.

The previous prime is 644663323366397. The next prime is 644663323366481.

It is a happy number.

644663323366446 is nontrivially palindromic in base 10.

It is a Curzon number.

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, 15342165225 + ... + 15342207243.

It is an arithmetic number, because the mean of its divisors is an integer number (10997967924900).

Almost surely, 2^{644663323366446} is an apocalyptic number.

644663323366446 is an abundant number, since it is smaller than the sum of its proper divisors (763076571020754).

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

644663323366446 is a wasteful number, since it uses less digits than its factorization.

644663323366446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78194.

The product of its digits is 1934917632, while the sum is 66.

The spelling of 644663323366446 in words is "six hundred forty-four trillion, six hundred sixty-three billion, three hundred twenty-three million, three hundred sixty-six thousand, four hundred forty-six".