25478821 has 2 divisors, whose sum is σ = 25478822. Its totient is φ = 25478820.

The previous prime is 25478809. The next prime is 25478857. The reversal of 25478821 is 12887452.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14516100 + 10962721 = 3810^2 + 3311^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25478821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25478861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12739410 + 12739411.

It is an arithmetic number, because the mean of its divisors is an integer number (12739411).

Almost surely, 2^25478821 is an apocalyptic number.

It is an amenable number.

25478821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25478821 is an equidigital number, since it uses as much as digits as its factorization.

25478821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 35840, while the sum is 37.

The square root of 25478821 is about 5047.6550000966. The cubic root of 25478821 is about 294.2567558213.

The spelling of 25478821 in words is "twenty-five million, four hundred seventy-eight thousand, eight hundred twenty-one".