1557386321009 has 2 divisors, whose sum is σ = 1557386321010. Its totient is φ = 1557386321008.

The previous prime is 1557386320891. The next prime is 1557386321039. The reversal of 1557386321009 is 9001236837551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1168783696609 + 388602624400 = 1081103^2 + 623380^2 .

It is a cyclic number.

It is not a de Polignac number, because 1557386321009 - 2²⁰ = 1557385272433 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1557386321039) 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, 778693160504 + 778693160505.

It is an arithmetic number, because the mean of its divisors is an integer number (778693160505).

Almost surely, 2^{1557386321009} is an apocalyptic number.

It is an amenable number.

1557386321009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1557386321009 is an equidigital number, since it uses as much as digits as its factorization.

1557386321009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1360800, while the sum is 50.

The spelling of 1557386321009 in words is "one trillion, five hundred fifty-seven billion, three hundred eighty-six million, three hundred twenty-one thousand, nine".