660523321 has 8 divisors (see below), whose sum is σ = 700111080. Its totient is φ = 621017088.

The previous prime is 660523291. The next prime is 660523327. The reversal of 660523321 is 123325066.

It can be written as a sum of positive squares in 4 ways, for example, as 211295296 + 449228025 = 14536^2 + 21195^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 660523321 - 2²⁵ = 626968889 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 660523321.

It is not an unprimeable number, because it can be changed into a prime (660523327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3276 + ... + 36493.

It is an arithmetic number, because the mean of its divisors is an integer number (87513885).

Almost surely, 2^660523321 is an apocalyptic number.

It is an amenable number.

660523321 is a deficient number, since it is larger than the sum of its proper divisors (39587759).

660523321 is a wasteful number, since it uses less digits than its factorization.

660523321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40763.

The product of its (nonzero) digits is 6480, while the sum is 28.

The square root of 660523321 is about 25700.6482603066. The cubic root of 660523321 is about 870.8888265139. Note that the first 4 decimals are identical.

Adding to 660523321 its reverse (123325066), we get a palindrome (783848387).

The spelling of 660523321 in words is "six hundred sixty million, five hundred twenty-three thousand, three hundred twenty-one".