1666424399 has 2 divisors, whose sum is σ = 1666424400. Its totient is φ = 1666424398.

The previous prime is 1666424381. The next prime is 1666424411. The reversal of 1666424399 is 9934246661.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666424399 is a prime.

It is a super-2 number, since 2×1666424399² = 5553940555165022402, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666424329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833212199 + 833212200.

It is an arithmetic number, because the mean of its divisors is an integer number (833212200).

Almost surely, 2^1666424399 is an apocalyptic number.

1666424399 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666424399 is an equidigital number, since it uses as much as digits as its factorization.

1666424399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1679616, while the sum is 50.

The square root of 1666424399 is about 40821.8617777289. The cubic root of 1666424399 is about 1185.5736506968.

The spelling of 1666424399 in words is "one billion, six hundred sixty-six million, four hundred twenty-four thousand, three hundred ninety-nine".