1666424387 has 4 divisors (see below), whose sum is σ = 1666768080. Its totient is φ = 1666080696.

The previous prime is 1666424381. The next prime is 1666424399. The reversal of 1666424387 is 7834246661.

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

It is a cyclic number.

It is not a de Polignac number, because 1666424387 - 2⁶ = 1666424323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666424381) 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, 164468 + ... + 174305.

It is an arithmetic number, because the mean of its divisors is an integer number (416692020).

Almost surely, 2^1666424387 is an apocalyptic number.

1666424387 is a deficient number, since it is larger than the sum of its proper divisors (343693).

1666424387 is an equidigital number, since it uses as much as digits as its factorization.

1666424387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343692.

The product of its digits is 1161216, while the sum is 47.

The square root of 1666424387 is about 40821.8616307488. The cubic root of 1666424387 is about 1185.5736478510.

The spelling of 1666424387 in words is "one billion, six hundred sixty-six million, four hundred twenty-four thousand, three hundred eighty-seven".