20011121 has 6 divisors (see below), whose sum is σ = 21669030. Its totient is φ = 18471648.

The previous prime is 20011099. The next prime is 20011139. The reversal of 20011121 is 12111002.

It can be written as a sum of positive squares in 3 ways, for example, as 1132096 + 18879025 = 1064^2 + 4345^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20011121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20011099 and 20011108.

It is not an unprimeable number, because it can be changed into a prime (20011171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 59036 + ... + 59373.

It is an arithmetic number, because the mean of its divisors is an integer number (3611505).

Almost surely, 2^20011121 is an apocalyptic number.

It is an amenable number.

20011121 is a deficient number, since it is larger than the sum of its proper divisors (1657909).

20011121 is a wasteful number, since it uses less digits than its factorization.

20011121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118435 (or 118422 counting only the distinct ones).

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

The square root of 20011121 is about 4473.3791478031. The cubic root of 20011121 is about 271.4920640676.

Adding to 20011121 its reverse (12111002), we get a palindrome (32122123).

The spelling of 20011121 in words is "twenty million, eleven thousand, one hundred twenty-one".