166205521 has 8 divisors (see below), whose sum is σ = 182560320. Its totient is φ = 150611472.

The previous prime is 166205519. The next prime is 166205569. The reversal of 166205521 is 125502661.

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 166205521 - 2¹ = 166205519 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 166205521.

It is not an unprimeable number, because it can be changed into a prime (166205321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189730 + ... + 190603.

It is an arithmetic number, because the mean of its divisors is an integer number (22820040).

Almost surely, 2^166205521 is an apocalyptic number.

It is an amenable number.

166205521 is a deficient number, since it is larger than the sum of its proper divisors (16354799).

166205521 is a wasteful number, since it uses less digits than its factorization.

166205521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380375.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 166205521 is about 12892.0720212075. The cubic root of 166205521 is about 549.8131828324.

The spelling of 166205521 in words is "one hundred sixty-six million, two hundred five thousand, five hundred twenty-one".