99865987409 has 2 divisors, whose sum is σ = 99865987410. Its totient is φ = 99865987408.

The previous prime is 99865987363. The next prime is 99865987423. The reversal of 99865987409 is 90478956899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 98299806784 + 1566180625 = 313528^2 + 39575^2 .

It is a cyclic number.

It is not a de Polignac number, because 99865987409 - 2¹⁶ = 99865921873 is a prime.

It is not a weakly prime, because it can be changed into another prime (99865987469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49932993704 + 49932993705.

It is an arithmetic number, because the mean of its divisors is an integer number (49932993705).

Almost surely, 2^99865987409 is an apocalyptic number.

It is an amenable number.

99865987409 is a deficient number, since it is larger than the sum of its proper divisors (1).

99865987409 is an equidigital number, since it uses as much as digits as its factorization.

99865987409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 352719360, while the sum is 74.

The spelling of 99865987409 in words is "ninety-nine billion, eight hundred sixty-five million, nine hundred eighty-seven thousand, four hundred nine".