19666531013 has 2 divisors, whose sum is σ = 19666531014. Its totient is φ = 19666531012.

The previous prime is 19666530997. The next prime is 19666531033. The reversal of 19666531013 is 31013566691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19172002369 + 494528644 = 138463^2 + 22238^2 .

It is a cyclic number.

It is not a de Polignac number, because 19666531013 - 2⁴ = 19666530997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19666531033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9833265506 + 9833265507.

It is an arithmetic number, because the mean of its divisors is an integer number (9833265507).

Almost surely, 2^19666531013 is an apocalyptic number.

It is an amenable number.

19666531013 is a deficient number, since it is larger than the sum of its proper divisors (1).

19666531013 is an equidigital number, since it uses as much as digits as its factorization.

19666531013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 87480, while the sum is 41.

The spelling of 19666531013 in words is "nineteen billion, six hundred sixty-six million, five hundred thirty-one thousand, thirteen".