644685083693 has 8 divisors (see below), whose sum is σ = 736834658880. Its totient is φ = 552548435040.

The previous prime is 644685083687. The next prime is 644685083717. The reversal of 644685083693 is 396380586446.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-644685083693 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 (644685083633) 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 7 ways as a sum of consecutive naturals, for example, 3124523 + ... + 3324456.

It is an arithmetic number, because the mean of its divisors is an integer number (92104332360).

Almost surely, 2^644685083693 is an apocalyptic number.

It is an amenable number.

644685083693 is a deficient number, since it is larger than the sum of its proper divisors (92149575187).

644685083693 is a wasteful number, since it uses less digits than its factorization.

644685083693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6463267.

The product of its (nonzero) digits is 89579520, while the sum is 62.

The spelling of 644685083693 in words is "six hundred forty-four billion, six hundred eighty-five million, eighty-three thousand, six hundred ninety-three".