644073071 has 4 divisors (see below), whose sum is σ = 672076272. Its totient is φ = 616069872.

The previous prime is 644073037. The next prime is 644073083. The reversal of 644073071 is 170370446.

It is a happy number.

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 644073071 - 2¹⁴ = 644056687 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 (644073091) 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 3 ways as a sum of consecutive naturals, for example, 14001566 + ... + 14001611.

It is an arithmetic number, because the mean of its divisors is an integer number (168019068).

Almost surely, 2^644073071 is an apocalyptic number.

644073071 is a deficient number, since it is larger than the sum of its proper divisors (28003201).

644073071 is a wasteful number, since it uses less digits than its factorization.

644073071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28003200.

The product of its (nonzero) digits is 14112, while the sum is 32.

The square root of 644073071 is about 25378.5947404501. The cubic root of 644073071 is about 863.5981708959.

The spelling of 644073071 in words is "six hundred forty-four million, seventy-three thousand, seventy-one".