644542507727 has 2 divisors, whose sum is σ = 644542507728. Its totient is φ = 644542507726.

The previous prime is 644542507711. The next prime is 644542507747. The reversal of 644542507727 is 727705245446.

644542507727 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644542507727 - 2⁴ = 644542507711 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644542507747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322271253863 + 322271253864.

It is an arithmetic number, because the mean of its divisors is an integer number (322271253864).

Almost surely, 2^644542507727 is an apocalyptic number.

644542507727 is a deficient number, since it is larger than the sum of its proper divisors (1).

644542507727 is an equidigital number, since it uses as much as digits as its factorization.

644542507727 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13171200, while the sum is 53.

The spelling of 644542507727 in words is "six hundred forty-four billion, five hundred forty-two million, five hundred seven thousand, seven hundred twenty-seven".