20879121 has 4 divisors (see below), whose sum is σ = 27838832. Its totient is φ = 13919412.

The previous prime is 20879113. The next prime is 20879129. The reversal of 20879121 is 12197802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (20879113) and next prime (20879129).

It is not a de Polignac number, because 20879121 - 2³ = 20879113 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20879129) 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, 3479851 + ... + 3479856.

It is an arithmetic number, because the mean of its divisors is an integer number (6959708).

Almost surely, 2^20879121 is an apocalyptic number.

It is an amenable number.

20879121 is a deficient number, since it is larger than the sum of its proper divisors (6959711).

20879121 is an equidigital number, since it uses as much as digits as its factorization.

20879121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6959710.

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 20879121 is about 4569.3676805440. The cubic root of 20879121 is about 275.3620399664.

The spelling of 20879121 in words is "twenty million, eight hundred seventy-nine thousand, one hundred twenty-one".