1866666689 has 2 divisors, whose sum is σ = 1866666690. Its totient is φ = 1866666688.

The previous prime is 1866666677. The next prime is 1866666727. The reversal of 1866666689 is 9866666681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1154844289 + 711822400 = 33983^2 + 26680^2 .

It is a cyclic number.

It is not a de Polignac number, because 1866666689 - 2²⁸ = 1598231233 is a prime.

It is not a weakly prime, because it can be changed into another prime (1866666619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 933333344 + 933333345.

It is an arithmetic number, because the mean of its divisors is an integer number (933333345).

Almost surely, 2^1866666689 is an apocalyptic number.

It is an amenable number.

1866666689 is a deficient number, since it is larger than the sum of its proper divisors (1).

1866666689 is an equidigital number, since it uses as much as digits as its factorization.

1866666689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26873856, while the sum is 62.

The square root of 1866666689 is about 43204.9382478438. The cubic root of 1866666689 is about 1231.2765052090.

The spelling of 1866666689 in words is "one billion, eight hundred sixty-six million, six hundred sixty-six thousand, six hundred eighty-nine".