2013821 has 2 divisors, whose sum is σ = 2013822. Its totient is φ = 2013820.

The previous prime is 2013787. The next prime is 2013833. The reversal of 2013821 is 1283102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1792921 + 220900 = 1339^2 + 470^2 .

It is a cyclic number.

It is not a de Polignac number, because 2013821 - 2⁶ = 2013757 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2013821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2013721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1006910 + 1006911.

It is an arithmetic number, because the mean of its divisors is an integer number (1006911).

2^2013821 is an apocalyptic number.

It is an amenable number.

2013821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2013821 is an equidigital number, since it uses as much as digits as its factorization.

2013821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 2013821 is about 1419.0916108553. The cubic root of 2013821 is about 126.2816618299.

Adding to 2013821 its reverse (1283102), we get a palindrome (3296923).

The spelling of 2013821 in words is "two million, thirteen thousand, eight hundred twenty-one".