644000943 has 16 divisors (see below), whose sum is σ = 898894080. Its totient is φ = 409341504.

The previous prime is 644000927. The next prime is 644001019. The reversal of 644000943 is 349000446.

It is not a de Polignac number, because 644000943 - 2⁴ = 644000927 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644000943.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644000143) 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, 6688 + ... + 36506.

It is an arithmetic number, because the mean of its divisors is an integer number (56180880).

Almost surely, 2^644000943 is an apocalyptic number.

644000943 is a deficient number, since it is larger than the sum of its proper divisors (254893137).

644000943 is a wasteful number, since it uses less digits than its factorization.

644000943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30158.

The product of its (nonzero) digits is 10368, while the sum is 30.

The square root of 644000943 is about 25377.1736605951. The cubic root of 644000943 is about 863.5659323519.

The spelling of 644000943 in words is "six hundred forty-four million, nine hundred forty-three", and thus it is an aban number.