166287409 has 4 divisors (see below), whose sum is σ = 166386420. Its totient is φ = 166188400.

The previous prime is 166287397. The next prime is 166287419. The reversal of 166287409 is 904782661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10112400 + 156175009 = 3180^2 + 12497^2 .

It is a cyclic number.

It is not a de Polignac number, because 166287409 - 2⁵ = 166287377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166287419) 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 3 ways as a sum of consecutive naturals, for example, 46942 + ... + 50359.

It is an arithmetic number, because the mean of its divisors is an integer number (41596605).

Almost surely, 2^166287409 is an apocalyptic number.

It is an amenable number.

166287409 is a deficient number, since it is larger than the sum of its proper divisors (99011).

166287409 is an equidigital number, since it uses as much as digits as its factorization.

166287409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99010.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 166287409 is about 12895.2475354295. The cubic root of 166287409 is about 549.9034640487.

The spelling of 166287409 in words is "one hundred sixty-six million, two hundred eighty-seven thousand, four hundred nine".