644710117 has 4 divisors (see below), whose sum is σ = 660434796. Its totient is φ = 628985440.

The previous prime is 644710103. The next prime is 644710189. The reversal of 644710117 is 711017446.

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

It can be written as a sum of positive squares in 2 ways, for example, as 25745476 + 618964641 = 5074^2 + 24879^2 .

It is a cyclic number.

It is not a de Polignac number, because 644710117 - 2¹¹ = 644708069 is a prime.

It is a super-2 number, since 2×644710117² = 831302269924307378, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644710817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7862278 + ... + 7862359.

It is an arithmetic number, because the mean of its divisors is an integer number (165108699).

Almost surely, 2^644710117 is an apocalyptic number.

It is an amenable number.

644710117 is a deficient number, since it is larger than the sum of its proper divisors (15724679).

644710117 is a wasteful number, since it uses less digits than its factorization.

644710117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15724678.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 644710117 is about 25391.1424910342. The cubic root of 644710117 is about 863.8828024083.

The spelling of 644710117 in words is "six hundred forty-four million, seven hundred ten thousand, one hundred seventeen".