644076720077 has 8 divisors (see below), whose sum is σ = 755981942016. Its totient is φ = 537145063632.

The previous prime is 644076720073. The next prime is 644076720083. The reversal of 644076720077 is 770027670446.

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

It is a cyclic number.

It is not a de Polignac number, because 644076720077 - 2² = 644076720073 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644076720073) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1243391093 + ... + 1243391610.

It is an arithmetic number, because the mean of its divisors is an integer number (94497742752).

Almost surely, 2^644076720077 is an apocalyptic number.

It is an amenable number.

644076720077 is a deficient number, since it is larger than the sum of its proper divisors (111905221939).

644076720077 is a wasteful number, since it uses less digits than its factorization.

644076720077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2486782747.

The product of its (nonzero) digits is 2765952, while the sum is 50.

The spelling of 644076720077 in words is "six hundred forty-four billion, seventy-six million, seven hundred twenty thousand, seventy-seven".