2161979 has 4 divisors (see below), whose sum is σ = 2236560. Its totient is φ = 2087400.

The previous prime is 2161967. The next prime is 2161987. The reversal of 2161979 is 9791612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2161979 - 2⁴ = 2161963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2161919) 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 3 ways as a sum of consecutive naturals, for example, 37247 + ... + 37304.

It is an arithmetic number, because the mean of its divisors is an integer number (559140).

2^2161979 is an apocalyptic number.

2161979 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

2161979 is a deficient number, since it is larger than the sum of its proper divisors (74581).

2161979 is an equidigital number, since it uses as much as digits as its factorization.

2161979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74580.

The product of its digits is 6804, while the sum is 35.

The square root of 2161979 is about 1470.3669609999. The cubic root of 2161979 is about 129.3055473723.

The spelling of 2161979 in words is "two million, one hundred sixty-one thousand, nine hundred seventy-nine".