19668613 has 2 divisors, whose sum is σ = 19668614. Its totient is φ = 19668612.

The previous prime is 19668599. The next prime is 19668647. The reversal of 19668613 is 31686691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16785409 + 2883204 = 4097^2 + 1698^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19668613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19668683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9834306 + 9834307.

It is an arithmetic number, because the mean of its divisors is an integer number (9834307).

Almost surely, 2^19668613 is an apocalyptic number.

It is an amenable number.

19668613 is a deficient number, since it is larger than the sum of its proper divisors (1).

19668613 is an equidigital number, since it uses as much as digits as its factorization.

19668613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 40.

The square root of 19668613 is about 4434.9310028455. The cubic root of 19668613 is about 269.9341997863.

The spelling of 19668613 in words is "nineteen million, six hundred sixty-eight thousand, six hundred thirteen".