166642281 has 27 divisors (see below), whose sum is σ = 261435447. Its totient is φ = 102239280.

The previous prime is 166642261. The next prime is 166642297. The reversal of 166642281 is 182246661.

The square root of 166642281 is 12909.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 24651225 + 141991056 = 4965^2 + 11916^2 .

It is not a de Polignac number, because 166642281 - 2⁵ = 166642249 is a prime.

It is a super-2 number, since 2×166642281² = 55539299633765922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (166642261) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 503286 + ... + 503616.

Almost surely, 2^166642281 is an apocalyptic number.

166642281 is the 12909-th square number.

166642281 is the 6455-th centered octagonal number.

It is an amenable number.

166642281 is a deficient number, since it is larger than the sum of its proper divisors (94793166).

166642281 is an equidigital number, since it uses as much as digits as its factorization.

166642281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694 (or 347 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The cubic root of 166642281 is about 550.2943669409.

Multiplying 166642281 by its sum of digits (36), we get a square (5999122116 = 77454²).

The spelling of 166642281 in words is "one hundred sixty-six million, six hundred forty-two thousand, two hundred eighty-one".