669208805 has 18 divisors (see below), whose sum is σ = 841156134. Its totient is φ = 511072144.

The previous prime is 669208781. The next prime is 669208817. The reversal of 669208805 is 508802966.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 535367044 + 133841761 = 23138^2 + 11569^2 .

It is not a de Polignac number, because 669208805 - 2²² = 665014501 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1330184 + ... + 1330686.

Almost surely, 2^669208805 is an apocalyptic number.

It is an amenable number.

669208805 is a deficient number, since it is larger than the sum of its proper divisors (171947329).

669208805 is an frugal number, since it uses more digits than its factorization.

669208805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1057 (or 531 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 44.

The square root of 669208805 is about 25869.0704316951. The cubic root of 669208805 is about 874.6894375407.

The spelling of 669208805 in words is "six hundred sixty-nine million, two hundred eight thousand, eight hundred five".