20839121 has 4 divisors (see below), whose sum is σ = 21023652. Its totient is φ = 20654592.

The previous prime is 20839109. The next prime is 20839129. The reversal of 20839121 is 12193802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12193802 = 2 ⋅6096901.

It can be written as a sum of positive squares in 2 ways, for example, as 490000 + 20349121 = 700^2 + 4511^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20839121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20839129) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92096 + ... + 92321.

It is an arithmetic number, because the mean of its divisors is an integer number (5255913).

Almost surely, 2^20839121 is an apocalyptic number.

It is an amenable number.

20839121 is a deficient number, since it is larger than the sum of its proper divisors (184531).

20839121 is a wasteful number, since it uses less digits than its factorization.

20839121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184530.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 20839121 is about 4564.9886089672. The cubic root of 20839121 is about 275.1860823210.

The spelling of 20839121 in words is "twenty million, eight hundred thirty-nine thousand, one hundred twenty-one".