166218155 has 4 divisors (see below), whose sum is σ = 199461792. Its totient is φ = 132974520.

The previous prime is 166218149. The next prime is 166218161. The reversal of 166218155 is 551812661.

It is a happy number.

166218155 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 is an interprime number because it is at equal distance from previous prime (166218149) and next prime (166218161).

It is not a de Polignac number, because 166218155 - 2⁸ = 166217899 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16621811 + ... + 16621820.

It is an arithmetic number, because the mean of its divisors is an integer number (49865448).

Almost surely, 2^166218155 is an apocalyptic number.

166218155 is a deficient number, since it is larger than the sum of its proper divisors (33243637).

166218155 is an equidigital number, since it uses as much as digits as its factorization.

166218155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33243636.

The product of its digits is 14400, while the sum is 35.

The square root of 166218155 is about 12892.5620029535. The cubic root of 166218155 is about 549.8271137049.

The spelling of 166218155 in words is "one hundred sixty-six million, two hundred eighteen thousand, one hundred fifty-five".