1666604419 has 2 divisors, whose sum is σ = 1666604420. Its totient is φ = 1666604418.

The previous prime is 1666604383. The next prime is 1666604491. The reversal of 1666604419 is 9144066661.

Together with next prime (1666604491) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is an emirp because it is prime and its reverse (9144066661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1666604419 - 2⁹ = 1666603907 is a prime.

It is a super-2 number, since 2×1666604419² = 5555140578860655122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1666604519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833302209 + 833302210.

It is an arithmetic number, because the mean of its divisors is an integer number (833302210).

Almost surely, 2^1666604419 is an apocalyptic number.

1666604419 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666604419 is an equidigital number, since it uses as much as digits as its factorization.

1666604419 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 186624, while the sum is 43.

The square root of 1666604419 is about 40824.0666641627. The cubic root of 1666604419 is about 1185.6163407590.

The spelling of 1666604419 in words is "one billion, six hundred sixty-six million, six hundred four thousand, four hundred nineteen".