1669940509 has 2 divisors, whose sum is σ = 1669940510. Its totient is φ = 1669940508.

The previous prime is 1669940497. The next prime is 1669940527. The reversal of 1669940509 is 9050499661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1253372409 + 416568100 = 35403^2 + 20410^2 .

It is a cyclic number.

It is not a de Polignac number, because 1669940509 - 2⁵ = 1669940477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1669940309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834970254 + 834970255.

It is an arithmetic number, because the mean of its divisors is an integer number (834970255).

Almost surely, 2^1669940509 is an apocalyptic number.

It is an amenable number.

1669940509 is a deficient number, since it is larger than the sum of its proper divisors (1).

1669940509 is an equidigital number, since it uses as much as digits as its factorization.

1669940509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 524880, while the sum is 49.

The square root of 1669940509 is about 40864.9055914730. The cubic root of 1669940509 is about 1186.4069076032.

The spelling of 1669940509 in words is "one billion, six hundred sixty-nine million, nine hundred forty thousand, five hundred nine".