644673376446 has 128 divisors (see below), whose sum is σ = 1451538579456. Its totient is φ = 189206302080.

The previous prime is 644673376411. The next prime is 644673376483.

644673376446 is nontrivially palindromic in base 10.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 644673376446.

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, 119669365 + ... + 119674751.

It is an arithmetic number, because the mean of its divisors is an integer number (11340145152).

Almost surely, 2^644673376446 is an apocalyptic number.

644673376446 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 644673376446, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (725769289728).

644673376446 is an abundant number, since it is smaller than the sum of its proper divisors (806865203010).

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

644673376446 is a wasteful number, since it uses less digits than its factorization.

644673376446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5846.

The product of its digits is 146313216, while the sum is 60.

The spelling of 644673376446 in words is "six hundred forty-four billion, six hundred seventy-three million, three hundred seventy-six thousand, four hundred forty-six".