166138309 has 4 divisors (see below), whose sum is σ = 166614700. Its totient is φ = 165661920.

The previous prime is 166138307. The next prime is 166138339. The reversal of 166138309 is 903831661.

166138309 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 67076100 + 99062209 = 8190^2 + 9953^2 .

It is a cyclic number.

It is not a de Polignac number, because 166138309 - 2¹ = 166138307 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166138307) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 237672 + ... + 238369.

It is an arithmetic number, because the mean of its divisors is an integer number (41653675).

Almost surely, 2^166138309 is an apocalyptic number.

It is an amenable number.

166138309 is a deficient number, since it is larger than the sum of its proper divisors (476391).

166138309 is an equidigital number, since it uses as much as digits as its factorization.

166138309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476390.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 166138309 is about 12889.4650393257. The cubic root of 166138309 is about 549.7390596909.

The spelling of 166138309 in words is "one hundred sixty-six million, one hundred thirty-eight thousand, three hundred nine".