644507080787 has 4 divisors (see below), whose sum is σ = 644922090120. Its totient is φ = 644092071456.

The previous prime is 644507080741. The next prime is 644507080799. The reversal of 644507080787 is 787080705446.

It is a happy number.

644507080787 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 644507080787 - 2¹⁰ = 644507079763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644507080487) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207502337 + ... + 207505442.

It is an arithmetic number, because the mean of its divisors is an integer number (161230522530).

Almost surely, 2^644507080787 is an apocalyptic number.

644507080787 is a deficient number, since it is larger than the sum of its proper divisors (415009333).

644507080787 is a wasteful number, since it uses less digits than its factorization.

644507080787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415009332.

The product of its (nonzero) digits is 10536960, while the sum is 56.

The spelling of 644507080787 in words is "six hundred forty-four billion, five hundred seven million, eighty thousand, seven hundred eighty-seven".