644377407 has 8 divisors (see below), whose sum is σ = 896525184. Its totient is φ = 410907288.

The previous prime is 644377397. The next prime is 644377417. The reversal of 644377407 is 704773446.

It is an interprime number because it is at equal distance from previous prime (644377397) and next prime (644377417).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 644377407 - 2¹⁵ = 644344639 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644377417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4669333 + ... + 4669470.

It is an arithmetic number, because the mean of its divisors is an integer number (112065648).

Almost surely, 2^644377407 is an apocalyptic number.

644377407 is a deficient number, since it is larger than the sum of its proper divisors (252147777).

644377407 is a wasteful number, since it uses less digits than its factorization.

644377407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9338829.

The product of its (nonzero) digits is 395136, while the sum is 42.

The square root of 644377407 is about 25384.5899513859. The cubic root of 644377407 is about 863.7341713175.

The spelling of 644377407 in words is "six hundred forty-four million, three hundred seventy-seven thousand, four hundred seven".