19668638 has 16 divisors (see below), whose sum is σ = 32313600. Its totient is φ = 8904600.

The previous prime is 19668613. The next prime is 19668647. The reversal of 19668638 is 83686691.

It is a junction number, because it is equal to n+sod(n) for n = 19668592 and 19668601.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4313 + ... + 7611.

It is an arithmetic number, because the mean of its divisors is an integer number (2019600).

Almost surely, 2^19668638 is an apocalyptic number.

19668638 is a deficient number, since it is larger than the sum of its proper divisors (12644962).

19668638 is a wasteful number, since it uses less digits than its factorization.

19668638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3583.

The product of its digits is 373248, while the sum is 47.

The square root of 19668638 is about 4434.9338213777. The cubic root of 19668638 is about 269.9343141538.

The spelling of 19668638 in words is "nineteen million, six hundred sixty-eight thousand, six hundred thirty-eight".