644466664446 has 64 divisors (see below), whose sum is σ = 1467786341376. Its totient is φ = 186899702400.

The previous prime is 644466664427. The next prime is 644466664459.

644466664446 is nontrivially palindromic in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 644466664446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2014230 + ... + 2312153.

It is an arithmetic number, because the mean of its divisors is an integer number (22934161584).

Almost surely, 2^644466664446 is an apocalyptic number.

644466664446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

644466664446 is an abundant number, since it is smaller than the sum of its proper divisors (823319676930).

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

644466664446 is a wasteful number, since it uses less digits than its factorization.

644466664446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4326497.

The product of its digits is 191102976, while the sum is 60.

The spelling of 644466664446 in words is "six hundred forty-four billion, four hundred sixty-six million, six hundred sixty-four thousand, four hundred forty-six".