166280821 has 16 divisors (see below), whose sum is σ = 193898880. Its totient is φ = 139645440.

The previous prime is 166280819. The next prime is 166280827. The reversal of 166280821 is 128082661.

It is a cyclic number.

It is not a de Polignac number, because 166280821 - 2¹ = 166280819 is a prime.

It is a super-2 number, since 2×166280821² = 55298622864868082, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166280827) 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 15 ways as a sum of consecutive naturals, for example, 188301 + ... + 189181.

It is an arithmetic number, because the mean of its divisors is an integer number (12118680).

Almost surely, 2^166280821 is an apocalyptic number.

It is an amenable number.

166280821 is a deficient number, since it is larger than the sum of its proper divisors (27618059).

166280821 is an equidigital number, since it uses as much as digits as its factorization.

166280821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1404.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 166280821 is about 12894.9920899549. The cubic root of 166280821 is about 549.8962018997.

The spelling of 166280821 in words is "one hundred sixty-six million, two hundred eighty thousand, eight hundred twenty-one".