166121609 has 8 divisors (see below), whose sum is σ = 169228608. Its totient is φ = 163033200.

The previous prime is 166121597. The next prime is 166121633. The reversal of 166121609 is 906121661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 166121609 - 2⁸ = 166121353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166121689) 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 7 ways as a sum of consecutive naturals, for example, 14084 + ... + 23034.

It is an arithmetic number, because the mean of its divisors is an integer number (21153576).

Almost surely, 2^166121609 is an apocalyptic number.

It is an amenable number.

166121609 is a deficient number, since it is larger than the sum of its proper divisors (3106999).

166121609 is an equidigital number, since it uses as much as digits as its factorization.

166121609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9295.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 166121609 is about 12888.8172071761. The cubic root of 166121609 is about 549.7206393961.

The spelling of 166121609 in words is "one hundred sixty-six million, one hundred twenty-one thousand, six hundred nine".