6669647645 has 6 divisors (see below), whose sum is σ = 8003796318. Its totient is φ = 5335572024.

The previous prime is 6669647641. The next prime is 6669647657. The reversal of 6669647645 is 5467469666.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 5335718116 + 1333929529 = 73046^2 + 36523^2 .

It is not a de Polignac number, because 6669647645 - 2² = 6669647641 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6669647641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 164354 + ... + 200876.

It is an arithmetic number, because the mean of its divisors is an integer number (1333966053).

Almost surely, 2^6669647645 is an apocalyptic number.

It is an amenable number.

6669647645 is a deficient number, since it is larger than the sum of its proper divisors (1334148673).

6669647645 is an frugal number, since it uses more digits than its factorization.

6669647645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73051 (or 36528 counting only the distinct ones).

The product of its digits is 39191040, while the sum is 59.

The square root of 6669647645 is about 81667.9107422248. The cubic root of 6669647645 is about 1882.3525367624.

The spelling of 6669647645 in words is "six billion, six hundred sixty-nine million, six hundred forty-seven thousand, six hundred forty-five".