644228206289 has 2 divisors, whose sum is σ = 644228206290. Its totient is φ = 644228206288.

The previous prime is 644228206273. The next prime is 644228206301. The reversal of 644228206289 is 982602822446.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 369250675600 + 274977530689 = 607660^2 + 524383^2 .

It is a cyclic number.

It is not a de Polignac number, because 644228206289 - 2⁴ = 644228206273 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644228206289.

It is not a weakly prime, because it can be changed into another prime (644228206189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322114103144 + 322114103145.

It is an arithmetic number, because the mean of its divisors is an integer number (322114103145).

Almost surely, 2^644228206289 is an apocalyptic number.

It is an amenable number.

644228206289 is a deficient number, since it is larger than the sum of its proper divisors (1).

644228206289 is an equidigital number, since it uses as much as digits as its factorization.

644228206289 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5308416, while the sum is 53.

The spelling of 644228206289 in words is "six hundred forty-four billion, two hundred twenty-eight million, two hundred six thousand, two hundred eighty-nine".