669991271 has 2 divisors, whose sum is σ = 669991272. Its totient is φ = 669991270.

The previous prime is 669991253. The next prime is 669991297. The reversal of 669991271 is 172199966.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 669991271 - 2¹⁴ = 669974887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669993271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334995635 + 334995636.

It is an arithmetic number, because the mean of its divisors is an integer number (334995636).

Almost surely, 2^669991271 is an apocalyptic number.

669991271 is a deficient number, since it is larger than the sum of its proper divisors (1).

669991271 is an equidigital number, since it uses as much as digits as its factorization.

669991271 is an evil number, because the sum of its binary digits is even.

The product of its digits is 367416, while the sum is 50.

The square root of 669991271 is about 25884.1895951950. The cubic root of 669991271 is about 875.0302121813.

The spelling of 669991271 in words is "six hundred sixty-nine million, nine hundred ninety-one thousand, two hundred seventy-one".