644327 has 2 divisors, whose sum is σ = 644328. Its totient is φ = 644326.

The previous prime is 644297. The next prime is 644341. The reversal of 644327 is 723446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644327 - 2¹⁰ = 643303 is a prime.

It is equal to p₅₂₃₈₈ and since 644327 and 52388 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 644296 and 644305.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322163 + 322164.

It is an arithmetic number, because the mean of its divisors is an integer number (322164).

2⁶⁴⁴³²⁷ is an apocalyptic number.

644327 is a deficient number, since it is larger than the sum of its proper divisors (1).

644327 is an equidigital number, since it uses as much as digits as its factorization.

644327 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 26.

The square root of 644327 is about 802.6998193596. The cubic root of 644327 is about 86.3711648604.

The spelling of 644327 in words is "six hundred forty-four thousand, three hundred twenty-seven".