19661317531 has 2 divisors, whose sum is σ = 19661317532. Its totient is φ = 19661317530.

The previous prime is 19661317451. The next prime is 19661317537. The reversal of 19661317531 is 13571316691.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19661317531 - 2²⁷ = 19527099803 is a prime.

It is a super-2 number, since 2×19661317531² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19661317537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9830658765 + 9830658766.

It is an arithmetic number, because the mean of its divisors is an integer number (9830658766).

Almost surely, 2^19661317531 is an apocalyptic number.

19661317531 is a deficient number, since it is larger than the sum of its proper divisors (1).

19661317531 is an equidigital number, since it uses as much as digits as its factorization.

19661317531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 102060, while the sum is 43.

The spelling of 19661317531 in words is "nineteen billion, six hundred sixty-one million, three hundred seventeen thousand, five hundred thirty-one".