2520781 has 2 divisors, whose sum is σ = 2520782. Its totient is φ = 2520780.

The previous prime is 2520779. The next prime is 2520797. The reversal of 2520781 is 1870252.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1798281 + 722500 = 1341^2 + 850^2 .

It is a cyclic number.

It is not a de Polignac number, because 2520781 - 2¹ = 2520779 is a prime.

It is a super-2 number, since 2×2520781² = 12708673699922, which contains 22 as substring.

Together with 2520779, it forms a pair of twin primes.

2520781 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2520481) 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, 1260390 + 1260391.

It is an arithmetic number, because the mean of its divisors is an integer number (1260391).

2^2520781 is an apocalyptic number.

It is an amenable number.

2520781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2520781 is an equidigital number, since it uses as much as digits as its factorization.

2520781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 2520781 is about 1587.6967594601. The cubic root of 2520781 is about 136.0958990573.

The spelling of 2520781 in words is "two million, five hundred twenty thousand, seven hundred eighty-one".