166121279 has 4 divisors (see below), whose sum is σ = 168224160. Its totient is φ = 164018400.

The previous prime is 166121261. The next prime is 166121321. The reversal of 166121279 is 972121661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 972121661 = 7 ⋅138874523.

It is a cyclic number.

It is not a de Polignac number, because 166121279 - 2⁸ = 166121023 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 (166171279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1051322 + ... + 1051479.

It is an arithmetic number, because the mean of its divisors is an integer number (42056040).

Almost surely, 2^166121279 is an apocalyptic number.

166121279 is a deficient number, since it is larger than the sum of its proper divisors (2102881).

166121279 is an equidigital number, since it uses as much as digits as its factorization.

166121279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2102880.

The product of its digits is 9072, while the sum is 35.

The square root of 166121279 is about 12888.8044053745. The cubic root of 166121279 is about 549.7202753898.

The spelling of 166121279 in words is "one hundred sixty-six million, one hundred twenty-one thousand, two hundred seventy-nine".