2180021 has 2 divisors, whose sum is σ = 2180022. Its totient is φ = 2180020.

The previous prime is 2179997. The next prime is 2180027. The reversal of 2180021 is 1200812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1999396 + 180625 = 1414^2 + 425^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2180021 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 2179978 and 2180005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2180027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090010 + 1090011.

It is an arithmetic number, because the mean of its divisors is an integer number (1090011).

2^2180021 is an apocalyptic number.

It is an amenable number.

2180021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2180021 is an equidigital number, since it uses as much as digits as its factorization.

2180021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 2180021 is about 1476.4894175036. The cubic root of 2180021 is about 129.6642420478.

Adding to 2180021 its reverse (1200812), we get a palindrome (3380833).

The spelling of 2180021 in words is "two million, one hundred eighty thousand, twenty-one".