2049821 has 2 divisors, whose sum is σ = 2049822. Its totient is φ = 2049820.

The previous prime is 2049797. The next prime is 2049823. The reversal of 2049821 is 1289402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1612900 + 436921 = 1270^2 + 661^2 .

It is a cyclic number.

It is not a de Polignac number, because 2049821 - 2¹⁰ = 2048797 is a prime.

It is a super-2 number, since 2×2049821² = 8403532264082, which contains 22 as substring.

Together with 2049823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2049823) 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 as a sum of consecutive naturals, namely, 1024910 + 1024911.

It is an arithmetic number, because the mean of its divisors is an integer number (1024911).

2^2049821 is an apocalyptic number.

It is an amenable number.

2049821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2049821 is an equidigital number, since it uses as much as digits as its factorization.

2049821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 2049821 is about 1431.7195954516. The cubic root of 2049821 is about 127.0297117745.

The spelling of 2049821 in words is "two million, forty-nine thousand, eight hundred twenty-one".