20001121 has 4 divisors (see below), whose sum is σ = 22858432. Its totient is φ = 17143812.

The previous prime is 20001083. The next prime is 20001139. The reversal of 20001121 is 12110002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12110002 = 2 ⋅6055001.

It is a de Polignac number, because none of the positive numbers 2^k-20001121 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (7), and also a Moran number because the ratio is a prime number: 2857303 = 20001121 / (2 + 0 + 0 + 0 + 1 + 1 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20001151) 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, 1428645 + ... + 1428658.

It is an arithmetic number, because the mean of its divisors is an integer number (5714608).

Almost surely, 2^20001121 is an apocalyptic number.

It is an amenable number.

20001121 is a deficient number, since it is larger than the sum of its proper divisors (2857311).

20001121 is an equidigital number, since it uses as much as digits as its factorization.

20001121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2857310.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 20001121 is about 4472.2612848536. The cubic root of 20001121 is about 271.4468330017.

Adding to 20001121 its reverse (12110002), we get a palindrome (32111123).

The spelling of 20001121 in words is "twenty million, one thousand, one hundred twenty-one".