20505121 has 32 divisors (see below), whose sum is σ = 26869248. Its totient is φ = 15206400.

The previous prime is 20505103. The next prime is 20505127. The reversal of 20505121 is 12150502.

It is a cyclic number.

It is not a de Polignac number, because 20505121 - 2¹¹ = 20503073 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20505095 and 20505104.

It is not an unprimeable number, because it can be changed into a prime (20505127) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 202971 + ... + 203071.

It is an arithmetic number, because the mean of its divisors is an integer number (839664).

Almost surely, 2^20505121 is an apocalyptic number.

It is an amenable number.

20505121 is a deficient number, since it is larger than the sum of its proper divisors (6364127).

20505121 is a wasteful number, since it uses less digits than its factorization.

20505121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 20505121 is about 4528.2580536007. The cubic root of 20505121 is about 273.7079711405.

Adding to 20505121 its reverse (12150502), we get a palindrome (32655623).

The spelling of 20505121 in words is "twenty million, five hundred five thousand, one hundred twenty-one".