16668019 has 4 divisors (see below), whose sum is σ = 17118544. Its totient is φ = 16217496.

The previous prime is 16668013. The next prime is 16668037. The reversal of 16668019 is 91086661.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16668019 is a prime.

It is a super-2 number, since 2×16668019² = 555645714768722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 450487 = 16668019 / (1 + 6 + 6 + 6 + 8 + 0 + 1 + 9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16668013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225207 + ... + 225280.

It is an arithmetic number, because the mean of its divisors is an integer number (4279636).

Almost surely, 2^16668019 is an apocalyptic number.

16668019 is a deficient number, since it is larger than the sum of its proper divisors (450525).

16668019 is an equidigital number, since it uses as much as digits as its factorization.

16668019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450524.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 16668019 is about 4082.6485276105. The cubic root of 16668019 is about 255.4433859829.

The spelling of 16668019 in words is "sixteen million, six hundred sixty-eight thousand, nineteen".