19798666 has 4 divisors (see below), whose sum is σ = 29698002. Its totient is φ = 9899332.

The previous prime is 19798643. The next prime is 19798679. The reversal of 19798666 is 66689791.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 11417641 + 8381025 = 3379^2 + 2895^2 .

It is an unprimeable number.

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, 4949665 + ... + 4949668.

Almost surely, 2^19798666 is an apocalyptic number.

19798666 is a deficient number, since it is larger than the sum of its proper divisors (9899336).

19798666 is an equidigital number, since it uses as much as digits as its factorization.

19798666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9899335.

The product of its digits is 979776, while the sum is 52.

The square root of 19798666 is about 4449.5691926298. The cubic root of 19798666 is about 270.5278471359.

The spelling of 19798666 in words is "nineteen million, seven hundred ninety-eight thousand, six hundred sixty-six".