1980208758509 has 2 divisors, whose sum is σ = 1980208758510. Its totient is φ = 1980208758508.

The previous prime is 1980208758481. The next prime is 1980208758629. The reversal of 1980208758509 is 9058578020891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1436169750409 + 544039008100 = 1198403^2 + 737590^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1980208758509 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1980208758109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990104379254 + 990104379255.

It is an arithmetic number, because the mean of its divisors is an integer number (990104379255).

Almost surely, 2^{1980208758509} is an apocalyptic number.

It is an amenable number.

1980208758509 is a deficient number, since it is larger than the sum of its proper divisors (1).

1980208758509 is an equidigital number, since it uses as much as digits as its factorization.

1980208758509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14515200, while the sum is 62.

The spelling of 1980208758509 in words is "one trillion, nine hundred eighty billion, two hundred eight million, seven hundred fifty-eight thousand, five hundred nine".