2540821 has 2 divisors, whose sum is σ = 2540822. Its totient is φ = 2540820.

The previous prime is 2540789. The next prime is 2540831. The reversal of 2540821 is 1280452.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1406596 + 1134225 = 1186^2 + 1065^2 .

It is a cyclic number.

It is not a de Polignac number, because 2540821 - 2⁵ = 2540789 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2540792 and 2540801.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2540831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1270410 + 1270411.

It is an arithmetic number, because the mean of its divisors is an integer number (1270411).

2^2540821 is an apocalyptic number.

It is an amenable number.

2540821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2540821 is an equidigital number, since it uses as much as digits as its factorization.

2540821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 2540821 is about 1593.9952948488. The cubic root of 2540821 is about 136.4555979147.

The spelling of 2540821 in words is "two million, five hundred forty thousand, eight hundred twenty-one".