644440516063306 has 4 divisors (see below), whose sum is σ = 966660774094962. Its totient is φ = 322220258031652.

The previous prime is 644440516063303. The next prime is 644440516063307. The reversal of 644440516063306 is 603360615044446.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 643840332732081 + 600183331225 = 25374009^2 + 774715^2 .

It is not an unprimeable number, because it can be changed into a prime (644440516063303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161110129015825 + ... + 161110129015828.

Almost surely, 2^{644440516063306} is an apocalyptic number.

644440516063306 is a deficient number, since it is larger than the sum of its proper divisors (322220258031656).

644440516063306 is a wasteful number, since it uses less digits than its factorization.

644440516063306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322220258031655.

The product of its (nonzero) digits is 14929920, while the sum is 52.

The spelling of 644440516063306 in words is "six hundred forty-four trillion, four hundred forty billion, five hundred sixteen million, sixty-three thousand, three hundred six".