644057 has 2 divisors, whose sum is σ = 644058. Its totient is φ = 644056.

The previous prime is 644053. The next prime is 644089. The reversal of 644057 is 750446.

644057 is nontrivially palindromic in base 16.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 502681 + 141376 = 709^2 + 376^2 .

It is a cyclic number.

It is not a de Polignac number, because 644057 - 2² = 644053 is a prime.

It is not a weakly prime, because it can be changed into another prime (644051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322028 + 322029.

It is an arithmetic number, because the mean of its divisors is an integer number (322029).

2⁶⁴⁴⁰⁵⁷ is an apocalyptic number.

It is an amenable number.

644057 is a deficient number, since it is larger than the sum of its proper divisors (1).

644057 is an equidigital number, since it uses as much as digits as its factorization.

644057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 644057 is about 802.5316193148. The cubic root of 644057 is about 86.3590987963.

The spelling of 644057 in words is "six hundred forty-four thousand, fifty-seven".