19660019 has 4 divisors (see below), whose sum is σ = 19908960. Its totient is φ = 19411080.

The previous prime is 19660013. The next prime is 19660027. The reversal of 19660019 is 91006691.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91006691 = 73 ⋅1246667.

It is a cyclic number.

It is not a de Polignac number, because 19660019 - 2⁸ = 19659763 is a prime.

It is a super-2 number, since 2×19660019² = 773032694160722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19660013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124352 + ... + 124509.

It is an arithmetic number, because the mean of its divisors is an integer number (4977240).

Almost surely, 2^19660019 is an apocalyptic number.

19660019 is a deficient number, since it is larger than the sum of its proper divisors (248941).

19660019 is an equidigital number, since it uses as much as digits as its factorization.

19660019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248940.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 19660019 is about 4433.9619980329. The cubic root of 19660019 is about 269.8948790596.

The spelling of 19660019 in words is "nineteen million, six hundred sixty thousand, nineteen".