20101121 has 4 divisors (see below), whose sum is σ = 20300244. Its totient is φ = 19902000.

The previous prime is 20101099. The next prime is 20101129. The reversal of 20101121 is 12110102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9610000 + 10491121 = 3100^2 + 3239^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101121 - 2¹⁰ = 20100097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20101099 and 20101108.

It is not an unprimeable number, because it can be changed into a prime (20101129) 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, 99410 + ... + 99611.

It is an arithmetic number, because the mean of its divisors is an integer number (5075061).

Almost surely, 2^20101121 is an apocalyptic number.

It is an amenable number.

20101121 is a deficient number, since it is larger than the sum of its proper divisors (199123).

20101121 is a wasteful number, since it uses less digits than its factorization.

20101121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199122.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 20101121 is about 4483.4273720001. The cubic root of 20101121 is about 271.8984671865.

Adding to 20101121 its reverse (12110102), we get a palindrome (32211223).

The spelling of 20101121 in words is "twenty million, one hundred one thousand, one hundred twenty-one".