644074007 has 4 divisors (see below), whose sum is σ = 645604296. Its totient is φ = 642543720.

The previous prime is 644073979. The next prime is 644074009. The reversal of 644074007 is 700470446.

644074007 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 644074007 - 2¹² = 644069911 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 (644074009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 764513 + ... + 765354.

It is an arithmetic number, because the mean of its divisors is an integer number (161401074).

Almost surely, 2^644074007 is an apocalyptic number.

644074007 is a deficient number, since it is larger than the sum of its proper divisors (1530289).

644074007 is a wasteful number, since it uses less digits than its factorization.

644074007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1530288.

The product of its (nonzero) digits is 18816, while the sum is 32.

The square root of 644074007 is about 25378.6131811807. The cubic root of 644074007 is about 863.5985892374.

The spelling of 644074007 in words is "six hundred forty-four million, seventy-four thousand, seven".