19662678517 has 2 divisors, whose sum is σ = 19662678518. Its totient is φ = 19662678516.

The previous prime is 19662678479. The next prime is 19662678521. The reversal of 19662678517 is 71587626691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18081105156 + 1581573361 = 134466^2 + 39769^2 .

It is a cyclic number.

It is not a de Polignac number, because 19662678517 - 2⁷ = 19662678389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19662678577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9831339258 + 9831339259.

It is an arithmetic number, because the mean of its divisors is an integer number (9831339259).

Almost surely, 2^19662678517 is an apocalyptic number.

It is an amenable number.

19662678517 is a deficient number, since it is larger than the sum of its proper divisors (1).

19662678517 is an equidigital number, since it uses as much as digits as its factorization.

19662678517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7620480, while the sum is 58.

The spelling of 19662678517 in words is "nineteen billion, six hundred sixty-two million, six hundred seventy-eight thousand, five hundred seventeen".