2517821 has 2 divisors, whose sum is σ = 2517822. Its totient is φ = 2517820.

The previous prime is 2517811. The next prime is 2517847. The reversal of 2517821 is 1287152.

It is an a-pointer prime, because the next prime (2517847) can be obtained adding 2517821 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2292196 + 225625 = 1514^2 + 475^2 .

It is a cyclic number.

It is not a de Polignac number, because 2517821 - 2¹⁸ = 2255677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2517811) 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, 1258910 + 1258911.

It is an arithmetic number, because the mean of its divisors is an integer number (1258911).

2^2517821 is an apocalyptic number.

It is an amenable number.

2517821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2517821 is an equidigital number, since it uses as much as digits as its factorization.

2517821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1120, while the sum is 26.

The square root of 2517821 is about 1586.7643177233. The cubic root of 2517821 is about 136.0426084776.

The spelling of 2517821 in words is "two million, five hundred seventeen thousand, eight hundred twenty-one".