25704821 has 2 divisors, whose sum is σ = 25704822. Its totient is φ = 25704820.

The previous prime is 25704787. The next prime is 25704871. The reversal of 25704821 is 12840752.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22515025 + 3189796 = 4745^2 + 1786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25704821 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25704871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12852410 + 12852411.

It is an arithmetic number, because the mean of its divisors is an integer number (12852411).

Almost surely, 2^25704821 is an apocalyptic number.

It is an amenable number.

25704821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25704821 is an equidigital number, since it uses as much as digits as its factorization.

25704821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 25704821 is about 5069.9922090670. The cubic root of 25704821 is about 295.1242261444.

The spelling of 25704821 in words is "twenty-five million, seven hundred four thousand, eight hundred twenty-one".