644080320787 has 8 divisors (see below), whose sum is σ = 652282500800. Its totient is φ = 635879372544.

The previous prime is 644080320743. The next prime is 644080320823. The reversal of 644080320787 is 787023080446.

644080320787 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 644080320787 - 2⁷ = 644080320659 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644080320787.

It is not an unprimeable number, because it can be changed into a prime (644080320187) 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, 768289 + ... + 1370557.

It is an arithmetic number, because the mean of its divisors is an integer number (81535312600).

Almost surely, 2^644080320787 is an apocalyptic number.

644080320787 is a deficient number, since it is larger than the sum of its proper divisors (8202180013).

644080320787 is a wasteful number, since it uses less digits than its factorization.

644080320787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 615885.

The product of its (nonzero) digits is 1806336, while the sum is 49.

The spelling of 644080320787 in words is "six hundred forty-four billion, eighty million, three hundred twenty thousand, seven hundred eighty-seven".