19997266 has 4 divisors (see below), whose sum is σ = 29995902. Its totient is φ = 9998632.

The previous prime is 19997251. The next prime is 19997267. The reversal of 19997266 is 66279991.

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., 15046641 + 4950625 = 3879^2 + 2225^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (19997267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4999315 + ... + 4999318.

Almost surely, 2^19997266 is an apocalyptic number.

19997266 is a deficient number, since it is larger than the sum of its proper divisors (9998636).

19997266 is an equidigital number, since it uses as much as digits as its factorization.

19997266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9998635.

The product of its digits is 367416, while the sum is 49.

The square root of 19997266 is about 4471.8302740601. The cubic root of 19997266 is about 271.4293923996.

The spelling of 19997266 in words is "nineteen million, nine hundred ninety-seven thousand, two hundred sixty-six".