20555121 has 16 divisors (see below), whose sum is σ = 28387584. Its totient is φ = 13221504.

The previous prime is 20555083. The next prime is 20555141. The reversal of 20555121 is 12155502.

It is not a de Polignac number, because 20555121 - 2⁷ = 20554993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20555141) 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 15 ways as a sum of consecutive naturals, for example, 9295 + ... + 11291.

It is an arithmetic number, because the mean of its divisors is an integer number (1774224).

Almost surely, 2^20555121 is an apocalyptic number.

It is an amenable number.

20555121 is a deficient number, since it is larger than the sum of its proper divisors (7832463).

20555121 is a wasteful number, since it uses less digits than its factorization.

20555121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2120.

The product of its (nonzero) digits is 500, while the sum is 21.

The square root of 20555121 is about 4533.7755789187. The cubic root of 20555121 is about 273.9302617908.

The spelling of 20555121 in words is "twenty million, five hundred fifty-five thousand, one hundred twenty-one".