644440745107 has 16 divisors (see below), whose sum is σ = 679933204000. Its totient is φ = 609107330304.

The previous prime is 644440745099. The next prime is 644440745147. The reversal of 644440745107 is 701547044446.

It is a cyclic number.

It is not a de Polignac number, because 644440745107 - 2³ = 644440745099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644440745147) 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, 15187573 + ... + 15229945.

It is an arithmetic number, because the mean of its divisors is an integer number (42495825250).

Almost surely, 2^644440745107 is an apocalyptic number.

644440745107 is a deficient number, since it is larger than the sum of its proper divisors (35492458893).

644440745107 is a wasteful number, since it uses less digits than its factorization.

644440745107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44230.

The product of its (nonzero) digits is 1505280, while the sum is 46.

The spelling of 644440745107 in words is "six hundred forty-four billion, four hundred forty million, seven hundred forty-five thousand, one hundred seven".