1666769009 has 2 divisors, whose sum is σ = 1666769010. Its totient is φ = 1666769008.

The previous prime is 1666768951. The next prime is 1666769017. The reversal of 1666769009 is 9009676661.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1192182784 + 474586225 = 34528^2 + 21785^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666769009 - 2²⁴ = 1649991793 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666769309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833384504 + 833384505.

It is an arithmetic number, because the mean of its divisors is an integer number (833384505).

Almost surely, 2^1666769009 is an apocalyptic number.

It is an amenable number.

1666769009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666769009 is an equidigital number, since it uses as much as digits as its factorization.

1666769009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 734832, while the sum is 50.

The square root of 1666769009 is about 40826.0824596238. The cubic root of 1666769009 is about 1185.6553690507.

The spelling of 1666769009 in words is "one billion, six hundred sixty-six million, seven hundred sixty-nine thousand, nine".