2120021 has 2 divisors, whose sum is σ = 2120022. Its totient is φ = 2120020.

The previous prime is 2120017. The next prime is 2120051. The reversal of 2120021 is 1200212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1416100 + 703921 = 1190^2 + 839^2 .

It is a cyclic number.

It is not a de Polignac number, because 2120021 - 2² = 2120017 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2119990 and 2120008.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2120051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060010 + 1060011.

It is an arithmetic number, because the mean of its divisors is an integer number (1060011).

2^2120021 is an apocalyptic number.

It is an amenable number.

2120021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2120021 is an equidigital number, since it uses as much as digits as its factorization.

2120021 is an odious number, because the sum of its binary digits is odd.

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

The square root of 2120021 is about 1456.0291892679. The cubic root of 2120021 is about 128.4635899407.

Adding to 2120021 its reverse (1200212), we get a palindrome (3320233).

It can be divided in two parts, 2 and 120021, that multiplied together give a palindrome (240042).

The spelling of 2120021 in words is "two million, one hundred twenty thousand, twenty-one".