20021121 has 32 divisors (see below), whose sum is σ = 32037120. Its totient is φ = 12310272.

The previous prime is 20021093. The next prime is 20021137. The reversal of 20021121 is 12112002.

It is not a de Polignac number, because 20021121 - 2¹¹ = 20019073 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23916 + ... + 24738.

It is an arithmetic number, because the mean of its divisors is an integer number (1001160).

Almost surely, 2^20021121 is an apocalyptic number.

It is an amenable number.

20021121 is a deficient number, since it is larger than the sum of its proper divisors (12015999).

20021121 is a wasteful number, since it uses less digits than its factorization.

20021121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 902 (or 896 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 20021121 is about 4474.4967314772. The cubic root of 20021121 is about 271.5372800674.

Adding to 20021121 its reverse (12112002), we get a palindrome (32133123).

It can be divided in two parts, 200 and 21121, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 20021121 in words is "twenty million, twenty-one thousand, one hundred twenty-one".