1666335889 has 2 divisors, whose sum is σ = 1666335890. Its totient is φ = 1666335888.

The previous prime is 1666335859. The next prime is 1666335907. The reversal of 1666335889 is 9885336661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1397638225 + 268697664 = 37385^2 + 16392^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666335889 - 2¹⁷ = 1666204817 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666335859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833167944 + 833167945.

It is an arithmetic number, because the mean of its divisors is an integer number (833167945).

Almost surely, 2^1666335889 is an apocalyptic number.

It is an amenable number.

1666335889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666335889 is an equidigital number, since it uses as much as digits as its factorization.

1666335889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5598720, while the sum is 55.

The square root of 1666335889 is about 40820.7776628520. Note that the first 3 decimals coincide. The cubic root of 1666335889 is about 1185.5526602493.

The spelling of 1666335889 in words is "one billion, six hundred sixty-six million, three hundred thirty-five thousand, eight hundred eighty-nine".