669543997 has 4 divisors (see below), whose sum is σ = 708928956. Its totient is φ = 630159040.

The previous prime is 669543949. The next prime is 669544009. The reversal of 669543997 is 799345966.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 307441156 + 362102841 = 17534^2 + 19029^2 .

It is a cyclic number.

It is not a de Polignac number, because 669543997 - 2¹⁹ = 669019709 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 (669543947) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19692454 + ... + 19692487.

It is an arithmetic number, because the mean of its divisors is an integer number (177232239).

Almost surely, 2^669543997 is an apocalyptic number.

It is an amenable number.

669543997 is a deficient number, since it is larger than the sum of its proper divisors (39384959).

669543997 is a wasteful number, since it uses less digits than its factorization.

669543997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39384958.

The product of its digits is 11022480, while the sum is 58.

The square root of 669543997 is about 25875.5482453996. The cubic root of 669543997 is about 874.8354507445.

The spelling of 669543997 in words is "six hundred sixty-nine million, five hundred forty-three thousand, nine hundred ninety-seven".