166266809 has 2 divisors, whose sum is σ = 166266810. Its totient is φ = 166266808.

The previous prime is 166266799. The next prime is 166266847. The reversal of 166266809 is 908662661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 110838784 + 55428025 = 10528^2 + 7445^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166266809 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166266809.

It is not a weakly prime, because it can be changed into another prime (166266869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83133404 + 83133405.

It is an arithmetic number, because the mean of its divisors is an integer number (83133405).

Almost surely, 2^166266809 is an apocalyptic number.

It is an amenable number.

166266809 is a deficient number, since it is larger than the sum of its proper divisors (1).

166266809 is an equidigital number, since it uses as much as digits as its factorization.

166266809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 166266809 is about 12894.4487668143. The cubic root of 166266809 is about 549.8807554159.

The spelling of 166266809 in words is "one hundred sixty-six million, two hundred sixty-six thousand, eight hundred nine".