644629 has 2 divisors, whose sum is σ = 644630. Its totient is φ = 644628.

The previous prime is 644617. The next prime is 644647. The reversal of 644629 is 926446.

644629 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 can be written as a sum of positive squares in only one way, i.e., 483025 + 161604 = 695^2 + 402^2 .

It is a cyclic number.

It is not a de Polignac number, because 644629 - 2⁵ = 644597 is a prime.

644629 is a lucky number.

It is a plaindrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 644629.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322314 + 322315.

It is an arithmetic number, because the mean of its divisors is an integer number (322315).

2⁶⁴⁴⁶²⁹ is an apocalyptic number.

It is an amenable number.

644629 is a deficient number, since it is larger than the sum of its proper divisors (1).

644629 is an equidigital number, since it uses as much as digits as its factorization.

644629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 31.

The square root of 644629 is about 802.8879124760. The cubic root of 644629 is about 86.3846569835.

The spelling of 644629 in words is "six hundred forty-four thousand, six hundred twenty-nine".