25563821 has 2 divisors, whose sum is σ = 25563822. Its totient is φ = 25563820.

The previous prime is 25563803. The next prime is 25563827. The reversal of 25563821 is 12836552.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24157225 + 1406596 = 4915^2 + 1186^2 .

It is a cyclic number.

It is not a de Polignac number, because 25563821 - 2⁶ = 25563757 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25563827) 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, 12781910 + 12781911.

It is an arithmetic number, because the mean of its divisors is an integer number (12781911).

Almost surely, 2^25563821 is an apocalyptic number.

It is an amenable number.

25563821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25563821 is an equidigital number, since it uses as much as digits as its factorization.

25563821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14400, while the sum is 32.

The square root of 25563821 is about 5056.0677408437. The cubic root of 25563821 is about 294.5836163363.

The spelling of 25563821 in words is "twenty-five million, five hundred sixty-three thousand, eight hundred twenty-one".