16660521 has 12 divisors (see below), whose sum is σ = 24103872. Its totient is φ = 11089176.

The previous prime is 16660519. The next prime is 16660531. The reversal of 16660521 is 12506661.

It is a happy number.

It is not a de Polignac number, because 16660521 - 2¹ = 16660519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16660531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6940 + ... + 9026.

It is an arithmetic number, because the mean of its divisors is an integer number (2008656).

Almost surely, 2^16660521 is an apocalyptic number.

It is an amenable number.

16660521 is a deficient number, since it is larger than the sum of its proper divisors (7443351).

16660521 is a wasteful number, since it uses less digits than its factorization.

16660521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2980 (or 2977 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 16660521 is about 4081.7301478662. The cubic root of 16660521 is about 255.4050770558.

The spelling of 16660521 in words is "sixteen million, six hundred sixty thousand, five hundred twenty-one".