1398768509 has 2 divisors, whose sum is σ = 1398768510. Its totient is φ = 1398768508.

The previous prime is 1398768487. The next prime is 1398768541. The reversal of 1398768509 is 9058678931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 805992100 + 592776409 = 28390^2 + 24347^2 .

It is a cyclic number.

It is not a de Polignac number, because 1398768509 - 2¹² = 1398764413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1398768599) 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, 699384254 + 699384255.

It is an arithmetic number, because the mean of its divisors is an integer number (699384255).

Almost surely, 2^1398768509 is an apocalyptic number.

It is an amenable number.

1398768509 is a deficient number, since it is larger than the sum of its proper divisors (1).

1398768509 is an equidigital number, since it uses as much as digits as its factorization.

1398768509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3265920, while the sum is 56.

The square root of 1398768509 is about 37400.1137565115. The cubic root of 1398768509 is about 1118.3608326750.

The spelling of 1398768509 in words is "one billion, three hundred ninety-eight million, seven hundred sixty-eight thousand, five hundred nine".