19915668637 has 2 divisors, whose sum is σ = 19915668638. Its totient is φ = 19915668636.

The previous prime is 19915668629. The next prime is 19915668659. The reversal of 19915668637 is 73686651991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19183912036 + 731756601 = 138506^2 + 27051^2 .

It is a cyclic number.

It is not a de Polignac number, because 19915668637 - 2³ = 19915668629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19915668607) 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, 9957834318 + 9957834319.

It is an arithmetic number, because the mean of its divisors is an integer number (9957834319).

Almost surely, 2^19915668637 is an apocalyptic number.

It is an amenable number.

19915668637 is a deficient number, since it is larger than the sum of its proper divisors (1).

19915668637 is an equidigital number, since it uses as much as digits as its factorization.

19915668637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14696640, while the sum is 61.

The spelling of 19915668637 in words is "nineteen billion, nine hundred fifteen million, six hundred sixty-eight thousand, six hundred thirty-seven".