640209617189 has 2 divisors, whose sum is σ = 640209617190. Its totient is φ = 640209617188.

The previous prime is 640209617147. The next prime is 640209617191. The reversal of 640209617189 is 981716902046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 607827614689 + 32382002500 = 779633^2 + 179950^2 .

It is a cyclic number.

It is not a de Polignac number, because 640209617189 - 2⁸ = 640209616933 is a prime.

Together with 640209617191, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640209617189.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640209617119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320104808594 + 320104808595.

It is an arithmetic number, because the mean of its divisors is an integer number (320104808595).

Almost surely, 2^640209617189 is an apocalyptic number.

It is an amenable number.

640209617189 is a deficient number, since it is larger than the sum of its proper divisors (1).

640209617189 is an equidigital number, since it uses as much as digits as its factorization.

640209617189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1306368, while the sum is 53.

The spelling of 640209617189 in words is "six hundred forty billion, two hundred nine million, six hundred seventeen thousand, one hundred eighty-nine".