640209368737 has 2 divisors, whose sum is σ = 640209368738. Its totient is φ = 640209368736.

The previous prime is 640209368731. The next prime is 640209368749. The reversal of 640209368737 is 737863902046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 514915315776 + 125294052961 = 717576^2 + 353969^2 .

It is a cyclic number.

It is not a de Polignac number, because 640209368737 - 2³¹ = 638061885089 is a prime.

It is not a weakly prime, because it can be changed into another prime (640209368731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320104684368 + 320104684369.

It is an arithmetic number, because the mean of its divisors is an integer number (320104684369).

Almost surely, 2^640209368737 is an apocalyptic number.

It is an amenable number.

640209368737 is a deficient number, since it is larger than the sum of its proper divisors (1).

640209368737 is an equidigital number, since it uses as much as digits as its factorization.

640209368737 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9144576, while the sum is 55.

The spelling of 640209368737 in words is "six hundred forty billion, two hundred nine million, three hundred sixty-eight thousand, seven hundred thirty-seven".