666565345 has 4 divisors (see below), whose sum is σ = 799878420. Its totient is φ = 533252272.

The previous prime is 666565343. The next prime is 666565363. The reversal of 666565345 is 543565666.

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 437981184 + 228584161 = 20928^2 + 15119^2 .

It is a cyclic number.

It is not a de Polignac number, because 666565345 - 2¹ = 666565343 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 666565295 and 666565304.

It is not an unprimeable number, because it can be changed into a prime (666565343) 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 3 ways as a sum of consecutive naturals, for example, 66656530 + ... + 66656539.

It is an arithmetic number, because the mean of its divisors is an integer number (199969605).

Almost surely, 2^666565345 is an apocalyptic number.

It is an amenable number.

666565345 is a deficient number, since it is larger than the sum of its proper divisors (133313075).

666565345 is a wasteful number, since it uses less digits than its factorization.

666565345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133313074.

The product of its digits is 1944000, while the sum is 46.

The square root of 666565345 is about 25817.9268145217. The cubic root of 666565345 is about 873.5362061797.

It can be divided in two parts, 6665 and 65345, that added together give a triangular number (72010 = T₃₇₉).

The spelling of 666565345 in words is "six hundred sixty-six million, five hundred sixty-five thousand, three hundred forty-five".