660550521 has 32 divisors (see below), whose sum is σ = 958832640. Its totient is φ = 402944256.

The previous prime is 660550507. The next prime is 660550531. The reversal of 660550521 is 125055066.

It is not a de Polignac number, because 660550521 - 2¹⁹ = 660026233 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (660550531) 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 31 ways as a sum of consecutive naturals, for example, 268720 + ... + 271166.

It is an arithmetic number, because the mean of its divisors is an integer number (29963520).

Almost surely, 2^660550521 is an apocalyptic number.

It is an amenable number.

660550521 is a deficient number, since it is larger than the sum of its proper divisors (298282119).

660550521 is a wasteful number, since it uses less digits than its factorization.

660550521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2613.

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 660550521 is about 25701.1774243905. The cubic root of 660550521 is about 870.9007805964.

The spelling of 660550521 in words is "six hundred sixty million, five hundred fifty thousand, five hundred twenty-one".