20505110121 has 16 divisors (see below), whose sum is σ = 31698721920. Its totient is φ = 13075722000.

The previous prime is 20505110113. The next prime is 20505110141. The reversal of 20505110121 is 12101150502.

It is not a de Polignac number, because 20505110121 - 2³ = 20505110113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20505110094 and 20505110103.

It is not an unprimeable number, because it can be changed into a prime (20505110111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16509130 + ... + 16510371.

It is an arithmetic number, because the mean of its divisors is an integer number (1981170120).

Almost surely, 2^20505110121 is an apocalyptic number.

It is an amenable number.

20505110121 is a deficient number, since it is larger than the sum of its proper divisors (11193611799).

20505110121 is a wasteful number, since it uses less digits than its factorization.

20505110121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33019533 (or 33019527 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 18.

Adding to 20505110121 its reverse (12101150502), we get a palindrome (32606260623).

The spelling of 20505110121 in words is "twenty billion, five hundred five million, one hundred ten thousand, one hundred twenty-one".