509949887861 has 2 divisors, whose sum is σ = 509949887862. Its totient is φ = 509949887860.

The previous prime is 509949887851. The next prime is 509949887903. The reversal of 509949887861 is 168788949905.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 407402634961 + 102547252900 = 638281^2 + 320230^2 .

It is a cyclic number.

It is not a de Polignac number, because 509949887861 - 2¹⁰ = 509949886837 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 (509949887851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 254974943930 + 254974943931.

It is an arithmetic number, because the mean of its divisors is an integer number (254974943931).

Almost surely, 2^509949887861 is an apocalyptic number.

It is an amenable number.

509949887861 is a deficient number, since it is larger than the sum of its proper divisors (1).

509949887861 is an equidigital number, since it uses as much as digits as its factorization.

509949887861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 313528320, while the sum is 74.

The spelling of 509949887861 in words is "five hundred nine billion, nine hundred forty-nine million, eight hundred eighty-seven thousand, eight hundred sixty-one".