669885509 has 2 divisors, whose sum is σ = 669885510. Its totient is φ = 669885508.

The previous prime is 669885499. The next prime is 669885547. The reversal of 669885509 is 905588966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 511754884 + 158130625 = 22622^2 + 12575^2 .

It is a cyclic number.

It is not a de Polignac number, because 669885509 - 2⁸ = 669885253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669885569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334942754 + 334942755.

It is an arithmetic number, because the mean of its divisors is an integer number (334942755).

Almost surely, 2^669885509 is an apocalyptic number.

It is an amenable number.

669885509 is a deficient number, since it is larger than the sum of its proper divisors (1).

669885509 is an equidigital number, since it uses as much as digits as its factorization.

669885509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4665600, while the sum is 56.

The square root of 669885509 is about 25882.1465299924. The cubic root of 669885509 is about 874.9841668972.

The spelling of 669885509 in words is "six hundred sixty-nine million, eight hundred eighty-five thousand, five hundred nine".