644033672063 has 16 divisors (see below), whose sum is σ = 665045089632. Its totient is φ = 623278656000.

The previous prime is 644033672027. The next prime is 644033672081. The reversal of 644033672063 is 360276330446.

It is a cyclic number.

It is not a de Polignac number, because 644033672063 - 2¹⁶ = 644033606527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644033672003) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14119073 + ... + 14164613.

It is an arithmetic number, because the mean of its divisors is an integer number (41565318102).

Almost surely, 2^644033672063 is an apocalyptic number.

644033672063 is a deficient number, since it is larger than the sum of its proper divisors (21011417569).

644033672063 is a wasteful number, since it uses less digits than its factorization.

644033672063 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48346.

The product of its (nonzero) digits is 1306368, while the sum is 44.

The spelling of 644033672063 in words is "six hundred forty-four billion, thirty-three million, six hundred seventy-two thousand, sixty-three".