19661668 has 24 divisors (see below), whose sum is σ = 37277240. Its totient is φ = 9020160.

The previous prime is 19661647. The next prime is 19661671. The reversal of 19661668 is 86616691.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 107584 + 19554084 = 328^2 + 4422^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8368 + ... + 10456.

Almost surely, 2^19661668 is an apocalyptic number.

It is an amenable number.

19661668 is a deficient number, since it is larger than the sum of its proper divisors (17615572).

19661668 is a wasteful number, since it uses less digits than its factorization.

19661668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2287 (or 2285 counting only the distinct ones).

The product of its digits is 93312, while the sum is 43.

The square root of 19661668 is about 4434.1479452089. The cubic root of 19661668 is about 269.9024247324.

It can be divided in two parts, 1 and 9661668, that added together give a palindrome (9661669).

The spelling of 19661668 in words is "nineteen million, six hundred sixty-one thousand, six hundred sixty-eight".