1666287787 has 2 divisors, whose sum is σ = 1666287788. Its totient is φ = 1666287786.

The previous prime is 1666287743. The next prime is 1666287803. The reversal of 1666287787 is 7877826661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1666287787 - 2¹¹ = 1666285739 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666288787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833143893 + 833143894.

It is an arithmetic number, because the mean of its divisors is an integer number (833143894).

Almost surely, 2^1666287787 is an apocalyptic number.

1666287787 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666287787 is an equidigital number, since it uses as much as digits as its factorization.

1666287787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9483264, while the sum is 58.

The square root of 1666287787 is about 40820.1884733523. The cubic root of 1666287787 is about 1185.5412523846.

The spelling of 1666287787 in words is "one billion, six hundred sixty-six million, two hundred eighty-seven thousand, seven hundred eighty-seven".